Next here tonight, an ABC news exclusive, every year 1,000 children are abducted by parents and taken overseas, and just this week, a senate panel has promised to help parents fighting to return their... See More
Next here tonight, an ABC news exclusive, every year 1,000 children are abducted by parents and taken overseas, and just this week, a senate panel has promised to help parents fighting to return their children to the United States. So, tonight, we're going to take you inside one of those cases. With the video that broke it open. And we tracked down the mother and two sons at the center of an extraordinary international manhunt. David Muir spending months on this trial. Reporter: This is incredible. 18 months go by, in fact, two dads, two ex-husbands I have no idea where their two beloved boys are, when suddenly a piece of evidence breaks the case wide open. Tonight, right here on "World news," you'll hear from fugitive mother herself when we track her down. Once upon a time -- Reporter: This is the story of two beautiful little boys. Two brothers. Like so many children across America tonight, they are boys who push the limits at bedtime. This is jerry. It's bedtime. No, it's not. Reporter: And then there's Sasha, laughing here as he jumps on the trampoline. Reporter: But the laughter from both boys goes silent. They vanish. Leaving on a summer vacation with their mother, they never come back. In California, two different fathers both once married to that woman, heartbroken over their boys. For 18 months, both of them asking, where are their sons? For months now, we've been documenting the international hunt. Jerry is everything to me. Without him, I can't live. I can't breathe. Can you hear his voice still? Oh, of course. It's strange because I feel like I'm with him all the time, except he's not here. Reporter: They rely on tips from perfect strangers all over the world. We follow the leads. Many are a bust. And then the biggest clue of all. Look at this. The stunning video. The boys playing at a resort in Slovakia, caught on tape more than a year after they disappeared. Their mother right there in those Orange shorts. And what's most startling to the fathers is how they look. Their long hair. One of the boys in pigtails. And that's Sasha to the left? That's Sasha in the pigtails disguised as a girl in the yellow shirt. Reporter: The fathers show us the video and the international dragnet tightening. We're with them as they fly to Geneva. We knock. There's no answer. Suddenly maria, who's now ready to speak with us. Do you think about them every moment? Every second. I love them more than my life. So why leave? Why take the boys and run? I didn't run. I left on a family vacation. I just didn't return.
This transcript has been automatically generated and may not be 100% accurate.