this is a special edition of "nightline." sex tourism takedown. >> americans are coming here for more than just the beautiful beaches. over 1 million children are sold here. and now, the unusual group on a dangerous rescue mission. a former fbi ability, even a hollywood actress, with a massive undercover operation. they need to catch them red-handed first. there's a girl 14 years old? >> i lied to them. >> and the stakes couldn't be higher for the girls or their

rescuers. this special edition of "nightline," sex tourism takedown, will be right back.

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not being carried out by police, but americans, who see themselves as iist abolitionists. david wright is there. >> reporter: heading out for a vacation, the clear blue water is only part of the allure. >> we have to play the part of tourists. >> reporter: the beauty of the girls attracts plenty of men willing to pay. >> i had this chick for two days. >> yeah. >> reporter: these guys are supposedly here for a surprise bachelor party. kim, the best man in charge of the money. marcus is bragging he can

arrange anything. >> this girl -- >> reporter: obviously, they're not talking poultry. they're after girls for the big party, and the younger, the better. but they have to speak in code, because what they're looking to do, hire underage prostitutes, is illegal here. marcus says to be careful. that's not to say he's unwilling to provide if the price is right. >> okay. of the girls that we already have that are sure, how many are min minor? >> seriously minor? six. >> what are the ages? >> 15, i got one 13.

>> this is a colombian operation. >> reporter: what's your cover story? >> we're down here doing a big party from the united states. a bunch of rich guys. i'm the best man from the wedding. my buddy is coming down, and we're going to surprise him with what he loves, child sex. >> reporter: he's a former investigator for homeland security. i imagine your work to be sort of the liam neeson character in "taken." >> the problem, the vast majority of kids, they weren't able to be saved. >> reporter: he believes he's rescuing children from slavery. a modern-day abolitionist.

operation under ground rail road has spent months in cooperation with the colombian officials. most of the pedophiles are sex tourists, with money and good jobs coming here for something exotic. it's 24 hours before the party. the team knows that tomorrow, anything can happen. >> here, okay, and then you're pivoting. >> reporter: so they're going over basic hand-to-hand moves. >> we're not down here on vacation, here to save children. >> reporter: s.e.a.l. team six,

this is not. but his group is a group of recruits for the sting operation. some off the books operatives, but many of them just regular citizens. and this man, a fitness instructor and a door to door salesman. that actress is laurie holden. have you ever done something like this? >> i spent time in cambodia. i was trained by a navy s.e.a.l. in "the walking dead." >> reporter: which is easier, this, or killing zombies? >> we'll see.

we'll see tomorrow. >> reporter: the group has led operations before in other countries. . >> we've been in the united states, haiti, ecuador. >> reporter: how about this group? are they legit? >> they're a legit and very professional group. >> reporter: they tell us it's not officially sanctioned by the u.s. government. but they're aware of it. many of our viewers saying, this is a noble thing. but there's something that feels like, this should be the work of governments. >> it absolutely should be. if the governments were doing it, we wouldn't be doing it. >> we got them. >> reporter: that's why they travel the world, gathering evidence to give to authoritiea.

and a camera crew is following them for a new film, "the abolitionists." and this multimillion-dollar mansion they rented. and this filmmaker wire the place for sound and video for the colombian officials to get evidence. for weeks, they've been putting the word out to gather girls for the party. thursday morning, the day of the party, they're getting set. almost showtime, huh? >> yes. >> reporter: are you nervous? >> yes, but it's good. >> i think it's going to be weird when we see the girls. it's going to set in, this is who's been sex trafficked. >> reporter: this sign making it

look like it's a teenager's birthday party. some of the men splash beer on their faces and clothes. >> i want them to smell plenty of beer on me. >> reporter: laurie holden's assignment, keep the girls busy in the pool while tim keeps the traffickers busy. >> this could be a big challenge, our hearts are going to break the second they walk in. >> reporter: but her fame could blow the group's cover. she's going to wear a brown wig. >> this could work. >> reporter: several different potential traffickers are coming, and their arrivals need

to be perfectly coordinated. and they're with the cti, colombia's version of the fbi. but there's a problem, one of the alleged traffickers are stuck in traffic. they have to get them here, and the girls to a safe place. and every second counts.

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our sex turnism takedown. the operation has been going for months, and the stakes are high. will it work? once again, here's abc's david wright. >> reporter: in colombia, the bachelor party is on. a parade of pretty young girls, ready to work. 30 in all. many of them are very young. the allege ed traffickers, trueo their word. but this isn't a typical bachelor party. upstairs, the authorities are waiting for the right moment to drop the hammer. tim is in on the sting. he's the leader of operation

underground rail road, who works with local authorities to catch pimps that sell underage girls for sex. your name is andrea? or that's what we'll call you? her parents have no idea she's a prostitute. she's 17, but has been working for six years. you started at the age of 11. do the men pay for more young girls? almost twice the price. she says she wishes she didn't do this.

at the party -- >> he brought like 100 girls. >> i'm missing three, because they're so late. >> 100 girls. 100! >> reporter: some of the girls are just 14 years old. >> of course, absolutely. they're giving eyes out, right. you know, trying to flirt with guys. >> reporter: one of the alleged traffickers singles out one girl. >> she's 14 years old. >> reporter: in order for the colombians to prosecute, there has to be no doubt. >> does she do everything? >> i have to talk to her. >> oral sex? there's not going to be any

problem? >> reporter: and money has to change hands. >> this is the good part. let me see. >> reporter: cold, hard cash right there on the table. this is the crucial moment investigators need to seal the deal. the man on the left there is a worker for the cti, colombia's version of the fbi. he gives the code word. the bust is on. >> what the heck? >> reporter: federal police to arrest the five alleged

traffickers, and social workers to help the girls. tim is playing his part, demanding to see his lawyer. so, is it worth it? >> worth what? >> reporter: to bring underage girls here. >> i lied to him about it. >> reporter: he says it's all just a misunderstanding. so, are you lying then or now? >> i wanted him to be happy with the girls i found. but no, there's not a single girl here that's underage. >> reporter: he says he has a daughter that's 15 back in the states. how could you do that? >> i'm not looking for young

girls. >> reporter: you think this is a total mistake? >> yes. you know why? because i did not look for young girls underage. >> reporter: but you seem to have brought some. >> please, check their i.d.s. >> reporter: i think they'll check more than than i.d.s. out by the pool, the social workers are one by one checking i.d.s. >> can i take my wig off? >> it's okay. >> reporter: many of the girls are afraid they're being arrested. this is their livelihood. for some of them, their main concern is to get paid for a night's work. not being arrested. >> some of them looked really terrified. i talked to a few of them and

asked how old they were. some were 12, 13, most were 14. one started to cry, and i started to cry. it's been very -- >> reporter: your heart goes out to them, huh? for these girls, it's a long road ahead. over the next few days, social services did interviews with them and their families. >> what makes me sad is that yes, we got four traffickers. and i hope they fry. but what makes me sad is i think so many of these little girls, they don't know any different.

>> reporter: and end up back out on the street? >> yeah. >> reporter: you think you did some good tonight? >> i know we did, but so much more needs to be done. >> reporter: any underage girl will be taken to a foster program to make sure they get the care they need. >> it's bittersweet. it's so horrific. i see my own children in this. >> reporter: but anyone of age is free to go. and in so many cases, even the youngest girls return to the streets. and sure enough, we saw some of the same girls, the ones thatra inconvenient ordeal.

david wright, for "nightline." and they told us they return to colombia in the fall, freeing 55 victims from sexual slavery. inside every ricola drop there's a magic herb blend. the swiss call itchrüterchraft. [electronic music} for powerful cough relief with a liquid menthol center that calms your cough.

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helped with the delivery. now, that's a christmas miracle. thank you for tuning in. "good morning america" tomorrow, and as always, we're online at abcnews.com. good night, america.

♪ >> welcome to inside the eagles. >> happy holidays, america. >> and everybody outside of america. center for leading children and myself we threw a huge holiday party. >> and jon, we will have season finally of tabo in the wolf's den. you and i will take on jewel van vandervelde i and andrew gardener. we have a story that will give new meaning to the term home for the holidays. >> they don't want butter they want parkay, first time on the show. you join us in the holiday section here. >> yes. >> that is really good. this is your first season. why don't you tell the fans what was the biggest surprise to you about the