. What was the single most important thing you think they needed to hear? That I didn't abandon them. He asked the whole world for help, and the world responded. A father's heart-wrenching plea on Facebook that went viral, shared nearly 1.5 million times. Shares, encouragement, even leads pouring in from around the globe. He's using social media... ...searching for them. He wanted them. Obsessed with finding the son and daughter he'd last seen when he'd been a young army sergeant in South Korea ` another country, another lifetime ago. The twins he'd been forced to leave behind but could never forget. You had no way of knowing it that day, as you boarded the plane, that was the last time you'd see your children. They were taken away from me. But if anyone can bring them back together again, it's this woman ` a professional people searcher. She is his best hope ` his last and only hope. He's been through hell and back. Work with me. Let's make this right. So, tonight come with us on an amazing search of a lifetime. Yeonghaseyo. A 45-year-old cold case, a mad dash across two continents... Yeonghaseyo. ...and 7000 miles. All the detective work,... Let's see how persuasive I can be. ...the detours... Nobody called you to say your kids are being adopted? Well, that's bull. They could've been separated. ...the blind alleys and brand-new leads,... I'm coming. You're not getting rid of me. ...the hope and the heartache. It's so messed up. And finally... I found both of them. No way. Way. They're both alive. Oh my God! The unforgettable emotion of a family about to be reunited. Are you ready to meet your twins? Tonight on 20/20 ` The Searchers. Captions were made with the support of NZ On Air. Copyright Able 2017 Kia Ora. I'm Carolyn Robinson. Tonight we're bringing you a story about a half century of hope. It starts in the 1960s in South Korea, where a young US army sergeant named Allen Thomas fell in love with a Korean woman. They had twins and got married. But when he got sent back to America, they couldn't come with him. So for the past 50 years, Allan Thomas has been searching for his children. Until a heart-felt plea on Facebook changed everything. Here's Elizabeth Vargas. GPS: Turn left on to US 12 East. It's very nice to meet you. So you're the young lady I will talk to, huh? I am the girl, hopefully, for the job. We flew Pam Slaton across country to Mossyrock, Washington, to join forces with former sergeant Allan Thomas. The retired veteran fought for his country. Now Pam vows to fight for him. If I don't get the answers I want, I'll work my way to the top, but I can assure you that if anyone's gonna try hard, it's gonna be me. So that much I can guarantee you, OK? Oh, that's all I can ask. OK. It's fair enough, I reckon. Well. Come on in. Here's to... Allen's daughter, Charlene, is helping her father on his four-decade quest to find the children she grew up knowing only as pictures on the wall. Charlene? Yes. Nice to meet you. You OK? Oh. These are for you. Pam brings flowers and hugs and hope. Give me a hug. This will be OK. This will be OK. I hope so. My name is Pamela Slaton. I'm an investigative genealogist, and my passion is reuniting people. I put in the biological father's name... You may remember Pam's work in a previous episode of 20/20 ` heart-warming, sometimes heart-stopping, revelations about missing loved ones. Yep. OK. Doc? Carson's showing up. On a never-ending search for the missing pieces of people's lives. With her husband, Mike, at the wheel, Pam's personal story is never far from her mind. She too was adopted and tracked down her birth mother. Now she's putting her years of experience to work for Allen Thomas. OK, this is better. His story begins in 1966. The year of Bonanza, the Beatles and the Baltimore Orioles. Baltimore wins 1-nothing, sweeping the series in four straight over the Dodgers. But half a world away, South Korea is still a divided and dangerous country with it's hair-trigger demilitarised zone. That is where the US army sent this 19-year-old GI to work on helicopters. And had you ever been overseas before? No, no. The first time I'd been overseas. It was exciting in a way and scared. Homesick. Korea had a thriving nightlife luring all those young American servicemen. And Allen soon met a woman at the non-commissioned officer's club. Her name was Seong-Kuem, but he had a very American nickname for his new companion. He called her Connie. She was five years older than him with a son from a previous relationship, named Jae-Im. What was she like? Short, petite. Mm-hm. Very nice. Then Connie got pregnant. Was that a surprise? Yeah, yeah. It was a great surprise as far as I was concerned. I think it was with her too, and, you know, so... Yeah, I was all for it, you know. When the time came, September 10th 1967, Allen rushed Connie to the hospital in Seoul and got another surprise. And when did you find out it was twins? Oh, I didn't find out it was twins till she had them. Are you kidding? No. Well, I remember that day, yeah. What was it like... you setting... eyes for the first time on these two little babies? I loved it. 'I got a family right now.' I was really super proud. Connie and the proud father named the twins Sandra and James. About a year later, as soon as the military would allow it, Allen married Connie and adopted her older son, Jae-Im. Judging by the old photos, the twins and their big brother were inseparable. They're really fond memories. But when his tour in Korea ended, Allen says he could not get his new family back to the United States. The twins were already American citizens with passports, but there was a problem with passports for Connie and Jae-Im. Allen figured it was just a matter of time and red tape. And we were corresponding, and she kept asking for money, so I kept sending them money. How often would you hear from her? You know, thinking back on it, (CHUCKLES) every time I heard from her, it seems like she wanted more money. I... Allen wanted to get back to Korea and his family so badly, he volunteered to serve in Vietnam, now a war at its worst, solely so that he could get 30 days' leave in Korea. More than 11,000 Americans would be killed in 1969 in Vietnam. Back home, the anti-war movement with its protest songs was in full swing. # Everybody look what's going down. # You asked to go to Vietnam in 1969. Oh, yes, ma'am. I figured if I went over there, I would extend and then I would go to Korea and get this situation squared away. You were hoping to be able to visit Korea... That's correct. Yep. ...visit your children and visit Connie? And see what was going on. And see what was going on. But when he finally got to Korea, more than a year had passed, and while he loved seeing the children, things with Connie were strained. A lot of things had changed. Like what? Our relationship. I could tell right off, and I sensed that things were different. He still remembers the day he had to leave to return to the war. Connie, the twins and Jae-Im went with him to the airport. I said my goodbyes, but when I turned and started walking to the plane, uh... no way... hard. It was hard? Just hard? Why ` because you'd had that special 30 days with your kids and`? I couldn't turn around. Why? Because I wouldn't leave. There is a snapshot from that day Allen has saved all these years. It shows little James saluting his dad, the sergeant. You had no way of knowing it that day, as you boarded the plane back for Vietnam, but that was the last time you would see your children? Mm-hm, yeah. Allen kept sending support, including US savings bonds, until his letters began bouncing back from Korea. And then he heard from Connie one last time. She wrote offering to hand over the twins, now 7 years old, if Allen would come get them. At that time I'd just gone through a bankruptcy. It was really hard, and there was just no way I could get over there. That's when, Allen says, Connie vanished somewhere in South Korea, taking the children with her. He couldn't even find her to serve the divorce papers. After a decade in the army, he married a woman from his hometown and began raising a family in Colorado. He went to work as a machinist in a factory, but even with his growing family in the United States, Allen never forgot about that family in South Korea. My mom had helped my dad search for so long. They did everything they could with the resources that they had. Um, but always seemed to run into roadblocks. Four decades' worth of roadblocks, but they are no match for searcher Pam Slaton. Help this man. Have compassion. He's been through hell and back. Work with me. Let's make this right. When we come back, a tear-stained letter that reveals stunning news about the whereabouts of Allen's twins. Are they closer than Allen ever realised? So will it be this easy for Pam to find Allen's lost children? Stay with us to find out. (GENTLE PIANO MUSIC) When you've got a hearing impairment, you're not aware of the effect it has on your family. Hearing aids can make life better for everyone. See if you're eligible for the $1000 government subsidy. Call us, or visit bayaudiology.co.nz. . Welcome back to 20/20 and tonight's story about one man's hunt for his lost twins. Former American army sergeant Allen Thomas has almost given up hope of finding the son and daughter he left behind in South Korea. As a last resort, he's turned to professional people searcher Pam Slaton, who's just had a major breakthrough. But as Elizabeth Vargas continues their story, we find out that nothing about the search is straightforward. The epic story of a soldier searching for his twins now leaps across time and distance from an army airfield in 1960s South Korea to the present day and a home in South Jersey. That's where we find Pam Slaton, and that's where she finds lost loved ones. There's probably 15` 20 cases in there. Pam Slaton is an author and a one-woman department of missing persons. 'Forced to give up my 7-year-old daughter.' And 'please help us find our son'. I don't think people can comprehend how many people are hurting and still out there trying to find somebody important in their life. But now a viral Facebook plea of 'help me find my twins' is about to spark a worldwide search led by Pam. Thank you. At her first meeting with veteran Allen Thomas, he shows her two letters that broke his heart. They arrived in the early 1980s from the state department and the Pearl S Buck Foundation ` an organisation that arranged adoptions for thousands on Asian-American children abandoned in Korea by their GI fathers. The letters informed Allen his Korean ex-wife Connie had given away their children, the twins, and amazingly the letter said he would have no legal right to his children. You must have been apoplectic. I mean, 'What do you mean they're adopted? I'm the father.' I was highly, highly upset. Where are my rights? I was told I had no rights. There was one piece of good news in that letter. It said that the twins had been adopted together in the United States. OK, so this is 1980 now. Is this the very first time that you're finding out these kids were adopted out to the US? Yes. This is it. Yep. Thank you very much. Appreciate it. Nice to meet you all. But since that letter, there have been no new clues... until now. Allen gets a mysterious Facebook message from Korea, from a man named Keon-su Lee. It turns out Lee is a policeman in Seoul specialising in finding missing children. A Korean version of Pam with a badge. He runs an investigative team in Korea and holds the world record for finding more than 3000 missing children. I feel like I need to get on a plane and go to Korea, but I don't speak the language. That's when the worldwide resources of ABC news went to work for Allen. In Seoul, South Korea, ABC News bureau chief Joohee Cho helps us pull back the curtain on the four-decade mystery. Annyeong sumnida. Sumnida. Her first stop is a meeting with Mr Lee. (SPEAKS KOREAN) TRANSLATOR: The most important thing for us is to figure out the mother's identity. Almost immediately a breakthrough. Lee finds the twin's mother, Allen's ex-wife Connie. She is listed in the Korean government registry. She gave birth to twins, and also she was married to (KOREAN PRONUNCIATION) Allen Thomas, so we were like, 'Bingo. Yay.' But the registry says Connie died in 2007. It was her heart. So Joohee's next stop, on the advice of Mr Lee, is Korea's social service, a small option agency. (SPEAKS KOREAN) Joohee mentions Connie's Korean name to the woman at the agency. When I told her the name of the Pae Seong-Kuem, she had twins, and there was this whole story on Facebook, I got a feeling that she knew who I was talking about, but she wouldn't admit it. The agency tells her Allen has no right to access the adoption records, but there is someone who does. She said... only siblings have rights... to ask for it. She gave me that hint. It was like, 'Wow, we didn't even know that loophole.' Remember little Jae-Im, the twin's older brother, the boy Allen adopted when he married Connie? Joohee finds him, all grown-up now, married with children. He now holds the key to finding the lost siblings, Allen's twins, back in America. The doors were locked unless Jae-Im gave you the key, in essence,... Yes. ...with his permission. Yes. But there's a problem. Even after all these years, Jae-Im resents Allen Thomas, the man who once adopted him, because he believes Allen abandoned them. When you first contacted Jae-Im, he wanted nothing to do with you. He said no. Joohee goes to visit Jae-Im and his wife in person. (ALL EXCHANGE GREETINGS IN KOREAN) Jae-Im remembers the day his little half brother and sister vanished. (SPEAKS KOREAN) TRANSLATOR: I came home after school, and they were gone. I asked my mother about the twins, and she told me they went somewhere, so I just accepted that. Joohee shares some insight about why Connie may have given up the twins for adoption. What would it have been like for these children in` growing up in South Korea, these GI babies? Impossible for their mothers to raise them, because they would have been disowned by their family if they stay... If they brought home a mixed-race baby? Yes, absolutely, and` It was considered that bad? Yes, it was considered that bad. Still reluctant, Jae-Im is finally persuaded by his wife to give permission to the adoption agency to release the records. Pam Slaton is in the US, ready to receive them. I woke up, and I could see that I got an email from Korea. And I couldn't even tell you how excited I was. This was the break she'd been waiting for. The email explains someone back in Korea had changed the twin's date of birth, making them appear to be a year younger and making tracing them nearly impossible. So you had spent all that time searching? Yes, yes. And had that birthday off by a year and a month? Yeah. But Pam is finding out nothing is easy with this search. And I start working my databases over and over again. I'm coming up empty again. Even with the correct birthdate? Even with the correct date of birth. Ever persistent, Pam goes looking for the twin's adoption records. There are copies in the archives of the Pearl S Buck Foundation in Pennsylvania. Pam calls but gets nowhere. And I said, 'Please let your boss know I'll be stopping by. I'll be in the area.' I was, kind of, like, 'I'm coming. You're not getting rid of me.' I am presently in Perkasie, Pennsylvania. I'm about to go see the Pearl Buck Foundation. I don't know what they're going to be willing to disclose to me. Let's see how persuasive I can be. Not persuasive enough, as it turns out. They still offer no help, because adoption records here are kept private by law. I got all Queens girl. You went Queens girl on her? I went Queens girl. Being the stubborn woman that I am, I called the agency back. 'Can you check what's known as the Order of Adoption?' She gets back on the phone. She's like, 'Wow.' She said, 'You're right. Their names were changed.' Hmm. Changed to what? Well, (LAUGHS) I said, 'For instance, Sandra, something may be similar to Sandra?' She said, 'Something similar.' (LAUGHS) Wow. 'What about James?' 'James' first name has completely changed,' she said. 'However, he did keep part of his name.' Well, that's telling me his first name, James, is now probably his middle name. So I said, 'Well, thank you very much. I will try not to bother you again.' So the two of you are basically playing a little game? We're playing a game. 'Cough if I'm close.' Right. (CHUCKLES) With the correct date of birth and information that Allen's son may have the middle name James, Pam dives back into her databases. So I figured, 'OK, let me pop James in the middle to see what I get.' And I'm going through all my lists, and then this one person, Timothy James Parker, catches my eye. Timothy James Parker, could he be half of the 40-year-old mystery? When we come back, Pam gives him a call. And someone answers his phone. I said, 'Is he a twin?' So is Timothy James Parker really Allen's son James? Stay with us to find out. . Welcome back to 20/20. Tonight we're following Allen Thomas, the former American soldier who spent the past half century trying to find the twins he left behind in South Korea. Helping in his search is Pam Slaton, who know believes she's found Allen's son James. But after all this time and so many dead-ends, Allen's trying not to get his hopes too high. Here's Elizabeth Vargas. The hunt for two missing children bridges two continents, Asia and North America; two cultures, East and West; and now the case is closer to being solved than at any time in nearly half a century. Thanks to two women, our searcher Pam Slaton and ABC news bureau chief Joohee Cho, who has just arrived in New York after a 14-hour flight. I'm Joohee. I know you are! (BOTH LAUGH) Nice to meet you. Nice to meet you. You did a lot. You're the key that unlocked the door. They've been working together on opposite sides of the world for several months. You know what I'm gonna do...? And now they're about to crack the case. After combing through countless false leads and phone numbers, Pam finds one that rings true. She finds the number for a man in Missouri named Timothy James Parker. Pam believes he could be Allen's long-lost son. He's not home when she calls, but a roommate answers. And I said, 'Well, is he by any chance Korean?' He said, 'Oh, yeah, he is.' I said, 'Oh`' I said, 'Is he a twin?' He says, 'Yeah.' Hmm. I said, 'He has a twin sister?' And he says, 'Yes, Susan.' I was like, 'Oh my gosh.' I mean` You did it. I had to contain myself. Now Pam has a name for the female twin, named Sandra when she was born in Korea. She is now Susan, living in Wisconsin. Now I jump on the computer. I run Susan Parker. Boom, there it is. Wow. And I just got goosebumps, cos it was this incredible moment. Are you with me? Pam gives her a call. She just got so emotional, so emotional straight out of the gates. Are you sitting down? After four decades, Pam had solved the puzzle in four months, but before Pam tells Allen what she's found,... Wish me luck. ...she calls Tim Parker again. This time he's home. I called back Tim, and he was a little bit non-trusting of me, and I assured him of my motives. I told him that I was helping someone that was very interested in knowing where he was. So you didn't say it was his father. I didn't say his father. I didn't. I felt like I needed to sit down with Mr Thomas before I did anything like that. And he said to me, 'I'm surprised. I didn't think anyone cared enough about me to look for me.' Tim said that? He did. And if he only knew. Wow. Pam believes this is the type of news you need to deliver in person. So she heads back out to Washington state. It's a case that felt overwhelming to me. And now that I get to get in a car today and go see Mr Thomas ` this man that's had a broken heart for 40 years ` to be able to sit in front of him and give him this news, I mean, that's incredible. It really is incredible. Hi. Hey, hello, hello. Come on in. My old friends. How are you? Oh, I'm fine, fine. How are you? Oh, I'm glad to see you. I'm so glad to see you guys. So, I just happened to be in the neighbourhood. Well, good. I hear you've got some fairly good news. Yeah, I've got progress, is what I have. Progress is good news. Oh. When Pam sits down with Charlene and Allen, he's girding for a legal battle. I'm the one that lost all the rights. Now all of a sudden, they're in the States. Now I've lost all my rights in the states and I can't find them. What law am I gonna go under? I still have a right to know who in hell adopted them. Allen still hasn't figured out why Pam has returned to his living room. He assumes the search has been in vain. Do you think I came all this way out here to show you paperwork? I don't know. I guess` I don't know. I thought I had to sign something so we could go to court. But if you need me to go to court, I'll go. We don't need to go to court. Why not? Well. Did you find out where they are? I found both of them. No way. Way. Wow! I found them. They're both alive. And they're in the States? They're in the States. Charlene seems to grasp the significance first. Oh my gosh. Allen looks stunned. I have been slowly chatting with your son. I spoke with him, and he doesn't know that you're searching for him yet, but he is expecting a call today if you're up to it. Oh my God! Oh, yes. Yeah, we're up for it. His immediate kneejerk reaction is 'do they want to talk to me? Is this gonna be OK?' And I said, 'They both actually want to talk to you.' He was afraid that they thought, and they had thought,... Mm-hm. ...that he had abandoned them. Right. And Allen's biggest fear is about to be confirmed. One of the things he said` I said, 'Did you ever think about finding anyone in your birth family?' And he said to me, 'I didn't think it was possible,' and he said, 'And quite honestly, I didn't think anyone ever cared enough about me to look for me.' But now, Dad` (SOBS) Now` Cos he was a little kid, and he couldn't know. He didn't understand, but now you're gonna be able to show him. That's gonna be such a blessing for him. It's so messed up. They felt abandoned. But, Dad, you didn't abandon them. I know that, but they didn't. And now he gets to know that. Yeah. After all those desperate decades, the moment Allen has waited for half his life is almost here. But when Pam offers to get the twins on the phone, Allen hesitates. It's all just too much. No, I just gotta get it together. They're here. They're here. I wanna get it together before I make the phone call. It's OK if you cry. It is OK. Anybody would cry. You didn't know` I gotta take a break here. Yeah, take a break. Coming up ` Allen makes that phone call. I've been searching a long time for you. And his long-lost twins call him a name he's been waiting 40 years to here. She called me Dad. After everything they went through, (SOBS) still called me Dad. And that emotional reunion is coming shortly when 20/20 returns. MAN: Look around. As the Favourites come out, it begins. Observing with an eagle eye. Mastering the art of stashing. Oh, brilliant move, Gran! Cadbury Favourites. . Welcome back to 20/20. As we continue, it looks like Allen Thomas is about to end his search for the twins he left behind in Korea. After learning the twins were adopted out to a family in the United States, searcher Pam Slaton has managed to track them down, and as Elizabeth Vargas continues the story, Allen's about to make contact with his son and daughter for the first time in almost half a century. After 40 years and many months of investigation, the story of what happened to Allen Thomas' twins, last seen in Korea, can finally be told. In May of 1976, a place from Seoul, South Korea, arrives at New York's Kennedy Airport. Aboard are two Korean children, brother and sister, twins. Allen Thomas' lost children coming to live in the same country as their father. If only he had known. Hi. Here she is, the twin Allen named Sandra now called Susan, all grown up. The little girl in those pictures all those years ago missing from her father's life for decades. Lost and now at long-last found. She says all she remembers as she and her brother flew to America is being alone. If there was a tearful heart-wrenching goodbye with their mother, Susan doesn't remember it. What do you remember about your mom? The sad thing is I don't remember much. Really? I see her off and on, in and out the door of the house. Mm-hm. And that's it. I don't recall anything about talking to her, hugs, kisses ` nothing like that. She wasn't affectionate with you? I don't recall. She does recall a stay in an orphanage in Korea and then a long flight to somewhere. We were in an airplane. We flew, and then we landed, and here's some people grabbing us. Someone that we don't even know. Speaking a language you didn't speak. No. I didn't even understand what they were saying either. Right. Oh, I have to just tell you, my heart just breaks. I'm about to cry, but I'm being very strong here. That's a really... traumatic thing to happen to two little children. Yes. She and her brother, originally James, now named Timothy James, are taken to their new home in rural Pennsylvania, where they and five other adopted children are all raised by Jean Parker, a single mother and a professor at this local university. Susan says someone back in Korea, probably in a misguided attempt to comfort her, had told her that if she didn't like America after 10 days, she could come home. So I counted 10 days, packed my stuff and start walking. So 10 days, you were like, 'OK, I'm done. I want to go home.' I'm ready. I've got my stuff ready. I'm walking. Didn't even realise that's overseas, but somehow I'm going. How far did you get? (CHUCKLES) End of the driveway. And what do you remember about Jean, the woman who adopted you? Amazing woman. I'm very grateful for this lady who adopted seven kids. Without her, I don't know where I'd be. Susan thrived in school. She was voted most studious and most athletic. She went on to get a degree in education. She lives in Wisconsin now with her husband and two children, who have never known their grandfather. Tim struggled finding his way in the world, but he's doing well now. He's a trucker and a driving instructor living in Missouri. They never heard from their biological mother, Connie, after coming to the United States. In college, Susan wrote her a letter. 'I am doing OK. How are you.' Stuff like that, but nothing mean. You didn't ask her`? I wanna say the first word was 'why, question mark', but, no. I didn't do that. You didn't write 'why'? No. What were you hoping for? I was hoping to get something back from her. Whether just a simple hi. Just something back saying, 'Hey, I'm OK,' and so on. But nothing. They moved. So you were never told that you had a father, who had been in your life for the first few years of your life? Never. Never seen the pictures. I haven't heard nothing about having a dad. Now Allen with his daughter, Charlene, by his side is about to speak to his newfound twins. They were 4 years old when he last saw them. They are now 48. Are you ready to do this? Yep. OK. I'm gonna dial this for you. What was your biggest fear? That they wouldn't want anything to do with me. What was the single-most important thing you think they needed to hear? That I didn't abandon them. That you always loved them, and you were always looking for them. Yep. They always had a family. Hi, Tim. Pam gets Tim on the phone. So, Tim, this has been a long road. I am actually working with your biological father. Biological father? Yes. Your American father has been searching for you for a long time, but let me explain what happened. Is he`? Wait, you're telling me he's still alive? I am telling you he's still alive, yes. Is this Tim? How you doing? And then it's time for a long overdue father-son talk. I've been looking for you for a long time, and I'm glad I finally got a hold of you. Wow, I just can't believe this is my actual father. Well, it is. Believe me. (CHUCKLES) The last time I saw you was in 1971 in Korea. I'm just very happy that you found me, and I'm happy that I'm talking to you. I have a father. Yes, of course, you've always had a father. We never forgot you. You've always been a member of this family. You didn't know it, but you always have been and always will be. And now it's time for Allen to talk to the other twin, his daughter Susan. He has missed so many milestones. Hello. OK, Susan, you're a hard girl to track down. I've been looking for you for quite a while. I just can't believe that this is real. I mean, I can't believe I'm talking to you. (SOBS) I know. I am too. It's hard, isn't it? And I know` I'm an all-grown woman, and here I am acting like a baby, crying. No, no, you're not. No, you're not. Besides that, you're still my baby, so... (SOBS) It's all right. (CRIES) It's OK. Making those emotional phone calls, Allen discovered something that concerned him. How long has it been since you and Tim have seen each other? The twins haven't seen each other, or even spoken, in 12 years. They can't even remember how they fell out of touch. But when we bring Tim and Susan to New York City,... Hi. Hi. Hi, Tim. I'm Elizabeth. Tim. And you know your sister. (CHUCKLES) The twins quickly embrace. How you doing? I've missed you. (SOBS) It's been too long. I gotta get a hug again. God, I missed you. Come have a seat. They've been speaking to Allen on the telephone, and they know the odyssey he endured to find them, including those changed birthdates. So you actually have a different birthdate? Yes. I hate to tell you guys you're older by a year than you thought you were. Thank you. Yeah. (LAUGHS) Not good news, Susan? Surrounded by images provided by Allen, Tim is brought back to his childhood. I remember that we took those pictures. And that's always on my mind. Photographs and phone calls are one thing, but what Allen really wants to do is put his arms around the children he lost when he was just a young father. Are you ready to meet your twins? Yeah. All right. Come on. Let's go. After more than 40 years, it is going to happen. You do not want to miss this emotional reunion. We'll be right back. . Welcome back. As we continue with tonight's story, The Searchers, Allen Thomas' hunt for his long-lost children is about to come to and end. After nearly 50 years apart from his twin son and daughter, he's about to reunited with them. Now Elizabeth Vargas has the emotional family reunion, but can it live up to expectations? Allen Thomas is about to have a face-to-face family reunion just about half a century in the making. Yeah. It's pretty awesome. Yeah, you guys did a pretty good job. A worldwide search launched by 20/20 located his long-lost twins in the United States. And the moment of truth is about to replace the mementos he's carried close to his heart all these years. That handful of photos. Yeah. It's all I had all these years, so I just... wherever I went, they went. We brought them all to New York, and as the twins approach, the expectations are building to a crescendo. I think we're just real excited to be able to see their face and touch them. Cos then it's real? Because` Yeah. To me, they still look like the little kids in the picture. Are you ready to meet your twins? Yeah. All right. Come on. For a long time. Let's go. How many years in the making? 40-something years. Susan. This is your dad. Tim, this is your dad. Come on. Come here. Come here. I missed you. (SOBS) Hi. (ALL SPEAK INDISTINCTLY, LAUGH) Oh, it's good to see you again. Yeah. Boy. A reunion with the most fantastic of expectations has been realised. You are my actual father. I'm standing right here looking at you, and I still not grasp that you are my father. We gave the twins their first look at their original birth certificates, which Allen had kept all these years. You see, that's the original copy. That was my name. James Allen Thomas. Put your first name as your middle name. Mm-hm. Timothy James. And a keepsake only a parent would cherish. This, here, I used to give you baths in, believe it or not. Both of you almost drowned a couple of times. But the old family photos bring up hard feelings for the twins sent away by their birth mother. Your mom looks kinda glamourous in that photo. She does. She looks very pretty. And you do look a lot like your mother. Every time I look at her, I just get frustrated. Me too. I do. Really? And forgive me for saying that. I mean... I do. ...there's some hatred in me ` of which I should never have that, but you're kinda mad, you know? It is a terrible way to remember your mother, but their half-brother, Jae-Im and his wife in Korea say there is another side to the story. (SPEAKS KOREAN) TRANSLATOR: My mother-in-law thought that Allen had left her and the kids because he met someone while he was in Vietnam. So why were the children sent to the US? TRANSLATOR: It meant huge success at the time to be going to America, equivalent to paradise. Everyone would dream of going to the land of the US. This your mother? ABC Seoul bureau chief Joohee Cho says Jae-Im and his wife believe Connie regretted giving the twins up for adoption. It seems to have haunted her until the day she died. She would just go to anyone in the neighbourhood and say, 'If you see any twins, Korean-American twins looking for Mrs Pae, that's me. That's me. 'Make sure that they call me,' and she would just look over the photo albums and her daughter-in-law said she just cry and touch the photos. Jae-Im has one more family secret hidden in an old ginseng box. It's a tin time capsule stuffed with mementos of a life that might've been ` snapshots of Connie, letters from Allen and, look at this, the savings bonds Allen sent all those years ago. She had saved them all her life. Is it possible she planned to give this modest inheritance to her twins one day when they returned? If so, that day never came. Allen's Facebook page is percolating tonight. Hundreds of well-wishers like the news of the big reunion. Few people in life, in their jobs have the chance to do something that changes somebody's life, which is what you've done for these three people. What is that like? It's amazing. I feel` I'm sorry. I don't know why I'm emotional. I've been doing this 20 years. (CHUCKLES) I feel blessed that people trust me enough to allow me into their world. It's an honour when you get to say, 'This is over. The healing's going to begin.' I'm a lucky girl. And the Thomas family feel lucky to be hitting New York City's Korea Town to remember their roots and catch up. The twins tease their dad, trying to get him to try the fermented Korean favourite kimchi. Nope. Just right there. But Allen is satisfied simply to savour their company and enjoy their first family dinner in 44 years. No. Take just a little taste. So a happy ending to a story almost 50 years in the making. That's our show for tonight. Thank you for joining us. Kia ora. Nga mihi.