this is "nightline." >> tonight americans released in a prisoner swap with iran. former marine now speaking out. >> just really feel proud to be an american. >> and what he did the moment the plane cleared iranian airspace. >> champagne bottles were popped. >> exchange one day before the anniversary of another hostage homecoming. plus, the story of autism spanning nearly two decades. tonight, the very first diagnosed case of autism. ground breaking therapies along the way and the surprising wonders found in unimagined places. and tonight the outspoken former governor sarah palin

billionaire donald trump in his 2016 bid for the white house sdl are you ready for a commander in chief who will let our warriors do their job? >> coming jury just days were iowa. but first, the "nightline 5." >> my sister raves about our mut wash. what? aren't they all the same? i went pro, with crest health pro advanced. >> this toothpaste and mouthwash make my whole mouth feel amazing and my teeth stronger. >> crest health pro advance is superior. >> this is going to go well for sure. >> advance to a healthier, stronger, cleaner mouth from day one. >> great checkup.

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thanks for joining us. i'm re world that iran did not break him. this on the 35th anniversary of another iran hostage crisis, leaving us with a strange feeling of deja vu. here's abc's david wright. >> reporter: tonight in germany "washington post" reporter jason rezaian laughed with his wife over a video. the first joke they've been able to share in more than a year. rezaian, one of five american citizens who were imprisoned in iran, all five of them free at last as part of a broader deal negotiated by the obama administration. >> at long last they can stand tall and breathe deep the fresh air of freedom. >> reporter: their release in exchange of iranian prisoners held here, part of a broader

since 1979. today 32-year-old amir hekmati was the first of the former prisoners to speak publicly. >> how does it feel to be back, amir? >> it feels great. i feel lucky. >> reporter: eager to let friends and family know he's okay. >> i didn't want to let my fellow marines down, so i tried my best to, you know, keep my head up and withstand all the pressures that were put upon me. some of which were very inhumane and unjust. i'm grateful. semper fi. >> reporter: he's a marine corps veteran, arrested while visiting family in iran. >> my name is amir hekmati. >> reporter: forced to make this false confession, convicted of espionage and sentenced to death. >> as soon as we got out of iranian airspace, champagne bottles were popped and the swiss are amazing, hospitality. >> reporter: the scene today a happy echo of 35 years ago this morning.

the 52 u.s. hostages -- >> look at that inside the door of the dc-9 welcome back to freedom. >> reporter: after 144 days of captivity. reporting for "nightline" that morning -- >> during these past 444 days. >> reporter: that's "nightline" anchor ted coppell introducing the late great peter jennings. >> it has been an unbelievably long day for the 52 american, 12 hours and 9 minutes after the islamic revolutionary guards finally released them and let them go. >> reporter: kevin just 20 years old then was the youngest of the hostages. >> i remember watching the footage. and you guys were so skinny and bearded and you looked like you had been through hell. >> we had. it's just we came out the other end, david. >> watching what's going on in iran right now, are you having some deja vu? >> well, i think so. clearly the events that are playing out right now halfway around the world bring back

>> reporter: he can remember every detail of those days. >> the state government of maine sent over 52 live lobsters for our first meal in freedom. >> you must think about that every time you eat lobster. >> i actually do. >> reporter: but for him and his fellow hostages the memories of their time inside are impossible to shake. >> if you were caught even whispering, sometimes even looking at your fellow american, you were immediately put into solitary confinement. i spent 43 days in solitary confinement, david, after trying to escape. >> reporter: that was a year before they were finally freed but their ordeal didn't end in. he says it was his family who helped him get through it. >> they're the ones that bring you back to reality, they're the ones who kick you out of the house and say it's time to earn a living. ptsd is a very real challenge. it is a very real problem. and i have a number of friends who were there in iran with me who to this day still suffer from that. >> reporter: harder still, for the family of bob levinson who

>> please help me. >> reporter: levinson was a former fbi agent who disappeared in iran nearly a decade ago. his captors sent proof of life three years ago but his wife and son learned the disappointing news he would not be coming home from watching tv. >> not a call from the white house? or the state department? >> no, nothing. >> reporter: heartbroken they spoke with my colleague brian ross. >> we're devastated. we had been given assurances over the years that my dad would be a top priority to get him home as much as everybody else, if not more, because he's been held for almost nine years. >> mrs. levinson, do you consider whether bob might have in fact died in captivity? >> no, i will never consider that until i have proof. i believe every day he's trying to come home to our family. we will never give up. >> our thoughts and prayers continue to be with the levinson family. the ordeal that they have been through over the last, you know, almost nine years now, is -- is

>> reporter: today the white house vowed the u.s. will continue to press iran for details on levinson's fate. >> we have reason to believe that he no longer is in iran. >> reporter: today the u.s. released. seven men convicted of helping iran's nuclear program and dropped charges against 14 more. but none of the iranians freed from u.s. custody elected to go back to iran. the obama administration's with iran remains hugely controversial. just as the iranian hostage crisis defined jimmy carter's presidency, ultimately dooming his re-election efforts, likewise the iran deal is at least a factor in the 2016 race. >> the fact is we shouldn't have to trade anything to get our citizens back home. >> we've got to shake our head at how it's happening. >> for one thing the republicans don't buy, iran's assurances that the country has suspended its nuclear weapons program. so what does the former hostage think? >> do you feel that president obama made a bad deal?

about getting the five men back this week or four men? >> the whole thing. >> i think the iranians got a better deal than we did. >> reporter: 35 years later, he still hasn't forgiven iran for the 444 days they stole from his life. but he has moved on with his life. he's able even to enjoy the movie "argo" which dealt with one chapter of the hostage crisis all those years ago but he says it was tough to watch. >> you don't want to totally relive even in story-telling the most tragic and difficult and darkest moments of a very bad period of your life. >> and this moment that we're living today must bring it all back but at least it brings back the best moment, which is the moment that you were freed. >> that is so true. you know i think when i am thinking about these guys returning home today, they're never going to be the person they were before they were captured. hopefully they will be a better person than they were. >> reporter: consider this,

freed by iran were held longer than the hostages were 35 years ago. they may be on their way back to the states, but it could be years before they feel truly home. i'm david wright for "nightline" in new york. next, a diagnosis that changed medical history in one mother's mission to fight for her son. then later, the endorsement for donald trump tonight in iowa reaction across the nation. here's a little healthy advice. eat well, live well,

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changed one person's life and the course of medical history. the first diagnosegagnosed case of autism, a life forever changed and one mother's whose journey helped millions of people and children who followed. >> reporter: you would never know it but this man helped make history in the anals of medicine he's known as case number one. his name is donald triplet. in 1943 he was the first person ever diagnosed with autism, the brain disorder that affects verbal and social interaction. and in many ways, his journey from despair to hope mirrors the history of autism itself. >> how are you? >> i'm all right. >> reporter: finding donald was the culmination of 15 years of reporting for "nightline" correspondent john donvan and producer caren zucker. >> reporter: this little boy is named jake. >> reporter: among the first

network television, they began in 2001 with jake, this little boy undergoing what was then a relatively uncommon therapy called applied behavior analysis, or aba. >> what do you call this little bit of progress? a miracle? no. because this is autism. >> jake. whoa. you're the best. >> and hard work has to take the >> reporter: and they found what some parents refer to as hope in unlikely spots, like on this beach in san diego where children with autism were finding some solace in learning how to surf. >> and it's about the point they're starting to paddle the first unwilling child into the swelling sea that you want to ask, is this really a good thing to be doing to these kids? whose idea was this anyway? >> reporter: they explored the private thoughts of a young man with autism looking for love. >> do you like her?

>> oh, you love her. >> but there's a problem. >> she don't love me back. >> she doesn't love you back. >> love unrequited, that's what's been weighing on paul. >> i just was rooting for him so hard so get what he wants, which is a girlfriend and love and companionship and also seeing just how hard it was for him to get that. >> our book is based here. >> reporter: arm we'd their scripts the duo have turned their first drafts of autism history into a comprehensive book "in a different key, the story of autism." >> your book is really a chronicle of a labor of love. >> "in a different key" is a story of all of these unsung heros who took their love and mobilized, literally, and any parent can relate to that. >> reporter: and that first

triplet's mom mary was a steely advocate for her son, removing him from a harsh institution and refusing to let him be marginalized. >> she was keeping up conversation, feeding him language all of the time. a boy who didn't really have much language and because of that, ultimately language began to come to him. >> yeah, better late than never. >> she taught him how to drive. >> yeah. >> kind of breathtaking. >> in what way was that an example of parental love, driving this whole evolution of our understanding of autism? >> it's never giving up. it's never taking no for an answer. he was 27 years old, i think, when he first learned how to drive. she was going to do everything she could in her power to give him a life. >> reporter: and at 82 donald today is still an enduring testament to his mother's love, a theme common throughout zucker and donvan's "nightline" stories.

looking back was it worth giving up your law practice, moving your house, relocating again. and 90% of the words that he has we taught him. so how much is a word worth, how much is one word worth? every word is priceless. >> reporter: the intimate access the pair received to these remarkable families was no accident. >> i have a 21-year-old son, mickey, who has autism. and when he was first diagnosed i. didn't know where to start. and as soon as i hit the ground running with him, i thought i have to just keep figuring out what's out there. and i have to share it with the world. >> like a true journalist. >> it was a little bit hard to say we want to do stories about autism, stories about what? about autism. it was only 16 years ago but really a lot has changed in the last 16 years. >> "nightline" was the only show who would do it. we didn't want for people to look for miracles. we wanted to show them what was

>> reporter: covering autism, organic transition from zucker immersed in the neurological disorder every day with her son. but donvan had a very different journalistic background. tell me about the evolution for you, of, you know, dashing foreign correspondent, you know, out on every breaking news story, to basically channeling your thoughts and your reporting towards one single topic. >> you can't do a story about a person with autism without sitting down and becoming -- forming a relationship. and in the beginning, i didn't know how. so it was a very big switch from action to very, very personal and intimate with somebody who i had to travel more than halfway to them to understand. >> what are the future chapters in the history of autism? >> adults. we have not looked at adults. >> as a society we've more or less, when these kids are kids let's give them an opportunity to have a great adulthoods.

that sort of goes down the drain in a lot of cases because people need continuing help but where are they? they're living at home with their parents often and for those 40 years after school, the person with autism has really not gone anywhere, not done anything. >> did you have a goal going into the book? >> caren, as a member of the community, at that time starting out you had a little boy, now you have a man -- i choke up over this. it's been a big -- >> what makes you emotional? >> her kid. i know that caren's always said what she wants is when her kid, now a man, is out there in the world, that she won't be the only one who has his back, that it will be everybody -- excuse me -- and she wants this book to get people who read it to be willing to be those people, to be there for her son.

>> reporter: for "nightline," i'm juju chang in new york. >> our thanks to juju, john, and caren for that powerful story. next, donald trump's new endorsement tonight heating up the race and igniting fiery reaction. abc news "nightline" brought to you by viagra. guys, it's just the two of you. the setting is just right. there's something in the air. but here's the thing: about half of men over 40 have some degree of erectile dysfunction. well, viagra helps guys with ed get and keep an erection. ask your doctor if your heart is healthy enough for sex. do not take viagra if you take nitrates for chest pain or adempas for pulmonary hypertension. your blood pressure could drop to an unsafe level. to avoid long-term injury, seek immediate medical help for an erection lasting more than four hours. stop taking viagra and call your doctor right away if you experience a sudden

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tonight sarah palin announced that she will officially be jumping onboard the let's make a america great again campaign. her endorsement getting mixed

give donald trump the boost he needs in iowa? >> i would like to bring up, if i might, governor sarah palin. >> reporter: tonight donald trump unveiling the newest feather in his campaign's cap. >> thank you so much. so great to be in iowa. >> an endorsement from former alaskan governor sarah palin. >> are you ready to make america great again? >> reporter: heating up the republican race with just 13 days to go before the iowa caucus. and palin's not mincing words. >> you ready for a commander in chief who will let our warriors do their job and go kick isis' [ bleep ]? >> reporter: they are close for years, both former reality stars. trump on "the apprentice" of course, and palin on "sarah palin's alaska." and she recently sang his praises on her talk show "on point with sarah palin." >> he is crushing it in the polls. >> thank you. >> reporter: the reaction in the