An unlikely take on fame from a man whos had it and lost it and now has it again. How mike posener has become a kind of antipop star. First the nightline 5. Looking for balance in your digestive system . Try align probiotic. For nonstop sweet treat goodness, hold on so your tiara kind of day. Live 24 7. Try align, the number one gerecommended probioti nutritional needs in one. Purina one. Healthy energy and a taste he loves. Purina one smart blend expertly blended with real meat number one. All in one, purina one. We begin tonight with the untold story of Kayla Mueller, the young humanitarian aid worker from arizona who fell into the hands of isis. A heartbreaking tale from her parents and for the first time from other young women imprisoned with kayla. They tell us about the brutality she endured and her bravery in the face of the infamous jihadi john. Heres abcs brian ross. Reporter the home movies show a young woman in love with life. Traveling the wld making her parents so proud. She just always had such a compassion for everybody around her. Youre always learning about yourself through other people, and youre always learning about life. And that process never stops. Reporter and then one morning at the home of marcia ago this month, came this. My name is Kayla Mueller. I need your help. Its very terrifying here. Reporter their 24yearold daughter kayla was in the hands of one of the most brutal terror groups the world has ever known. Isis. You just go into almost a catatonic state, i think. You just cant even stand up. Reporter karl owned an auto repair shop. Marcia a former nurs saw her strength. She was very strong in what she said. Reporter nothing prepared the muellers for what was about to happen. This kind of thing tears people apart. Reporter kayla had crossed into syria at this border checkpoint. Going along with a friend hired to install Communications Equipment for the humanitarian Group Doctors without borders. It was august 3rd, 2013. Less than 24 hours after leaving here, Kayla Mueller would be described as a hell on earth. Captured, imprisoned, tortured, raped. No one yet knew or could even imagine just how brutal isis could be to its hostages. Fear. Its fear of unknown. You dont know what is going to happen. Reporter as her fellow female hostages describe it to abc news, isis was Holding Kayla in a 12 foot by 12 foot room with a single lightbulb hanging from the ceiling. There was a little bit of but that was it. It was cold. Dirty. Reporter after being alone for several months, kayla was joined by three more women. They gave us black dresses and covered our hair and faces. Reporter for the first time two kaylas former cellmates are talking publicly about what happened to kayla and them at we realized that they were actually killers. That they would enjoy killing us. Reporter the prison they shared with kayla was located outside the isis headquarter city of raqqah, syria. She had a strong faith that gave her a lot of strength. Reporter their isis guards were led by the british recruit who would later be dubbed jihadi john. I think it was clear that they hated americans. Shed scream at her. They would blame her for everythiha reporter back in arizona, kaylas parents held out hope that isis would treat an aid worker gently, that one of the humanitarian groups she was connected to would help negotiate her freedom. But that did not happen. No one would claim her. So they assumed she was a spy. And we found out that her fingernails had been pulled out. Her hair had been shaved. A negotiated release grew increasingly unlikely as the muellers found themselves up against the u. S. Policy not to make concessions to terrorists. I firmly hold that the United States government paying ransom to terrorists risks endangering more americans and funding the very terrorism that were trying to stop. Reporter so as hostages from other countries which allow ransom payments were released by isis, kayla was left behind. It was a be released, looking forward to being released, but at the same time leaving someone behind. Whatd you say to her . Stay strong. This will end one day. Reporter finally, in late may, 2014, isis made contact with the muellers in this email, likely written by one of the british isis guards. The conditions of kaylas returning home safely are no emails, a followup with kaylas actual voice laying out the kidnappers latest demands, including the release of a pakistani woman being held in a u. S. Prison. If this is not achievable, they are demanding 5 Million Euros to ensure my release. Goodbye. Reporter the muellers say the white house stuck to its policy of no ransom. You asked to meet with president obama. He refused. We did meet in the white house. With many highranking reporter and no one in the white house told them what was about to happen. U. S. Special forces, which had carried out a number of successful highrisk rescue missions like this one, had been authorized to launch over the july fourth weekend a secret operation for kayla and some 18 other hostages. It turned out that the hostages were not longer at that location. Reporter one week later, in arizona. Your arrogant government attempted to do, your daughter has 30 days to live. If you fail to meet this deadline well send you a picture of kaylas dead body. My name is karl mueller, this is my wife marcia. Reporter as the 30day deadline approached the mulers recorded this dramatic personal plea, scripted largely by the fbi and sent to the new isis leader al baghdadi. Please, show mercy and this is a plea for kaylas life. We are asking for your mercy for kayla, as we believe you are the only one who can grant us this. Reporter it seemed to have worked. The deadline for kaylas execution, on her birthday, august 14th, passed with no word of her fate. A sigh of relief. And a hope that she had seen this part of the video herself. We know god is comforting you shortlived moment of relief. Today the entire world is appalled by the brutal murder of jim foley by the terrorist group isil. Reporter the first of kaylas fellow american hostages to be murdered. Again, the muellers asked to meet with president obama. We were told no. Reporter a few weeks later, another american hostage killed, journalist steven satloff. Now president obama agree the president was i felt very cold. We were told many times, were doing everything we can, and they werent. They were not . No, they werent. Reporter later, white house officials would threaten the muellers and other hostage families with criminal prosecution if they tried to pay ransom to gain their loved ones freedom. I had come to a point where our government is not going to bring kayla home. They are not going to bring kayla home. Reporter but as dark and as hopeless as it seemed to the muellers, they did receive one piece of what was described by the fbi as good news. They told us she had been actually taken out of the prison by abu bakr al baghdadi, the khalif of isis. They believed she was with a family, that she was safe. So my thought was, oh, good, kaylas able to maybe take care of the children, she reporter nothing could have been further from the truth, as the muellers later discovered. The socalled family where their daughter was safe was in fact Holding Kayla for the leader of isis, al baghdadi. And thats when they said he married her. Thats the way they put it. Their way of saying he raped her. Baghdadi chose her. Look at the symbolism in that. My dear, beautiful kayla, i miss you and love you. Yesterday, friday, at about 10 00 a. M. , we were called good evening, we begin with the breaking headline he told us it was out on twitter. The last american hostage held by isis that you had been killed by a Jordanian Air strike. Kayla mueller, 26 years old, is dead. My eyes are clouding up. Sorry. Still not believing the horrific people had lied so much and were so evil. Reporter precisely how kayla was killed remains a mystery. But the muellers refuse to believe that kayla was dead until isis a few days later sent three photos of kaylas body. I just kept still writing to hey, sweetheart. Have so much to share. You, young lady, have taught me so very much. I will see you soon. Love, mom. Since kaylas death the Obama Administration has promised that it will now allow families to privately raise ransom money without the threat of prosecution. Our thanks to brian ross and his team f next on nightline, you might not know mike poseners name but youve probably heard his song about taking a pill. Behind the scenes with a man whos become a sort of antipop star. With my moderate to severe ulcerative colitis, was almost always on my mind. Thinking about what to avoid, where to go. And how to deal with my uc. Helps people like me get uc under control and keep it under control when certain medications havent worked well enough. Humira can lower your ability to fight infections, including tuberculosis. Serious, sometimes fatal infections and cancers, including lymphoma, have happened; as have blood, liver, and nervous system problems, serious allergic reactions, and new or worsening heart failure. Before treatment, get tested for tb. Tell your doctor if youve been to areas where certain fungal infections are common, and if youve had tb, hepatitis b, are prone to infections, dont start humira if you have an infection. Raise your expectations. Ask your gastroenterologist about humira. With humira, control is possible. . Theres no one road out there. No one surface. No one speed. No one way of driving on each and every road. But there is one car that can conquer them all. The mercedesbenz cclass. To fit the mood youre in. And the road youre on. The 2016 cclass. Lease the c300 for 369 a month at your local mercedesbenz dealer. Put some distance between you and temptation with. Meta appetite control. Clinically proven to help reduce hunger between meals. When you can take your hands off the wheel to get out of a tight spot. When you can relax with your foot off the brake and stay put. And when you enjoy 400 horsepower thats both smooth and controlled. During the final days of the lincoln summer invitation sales event. Lease a lincoln mkc for 289 a month or get 0 apr for 60 months being a pop star looks fun on the surface at least. Screaming crowds, large paychecks, et cetera. Tonight meet a pop star who has a fascinating take on what many consider to be the dream life. This is a guy who has earned fame and lost it then earned it back again. Abcs Rebecca Jarvis goes behind the scenes with mike posner. Reporter its a summer night in new york city. . Mike poser in has got a soldout crowd of thousands on their feet. You might not know his name. . Took a pill . Reporter chances are youve been rocking out to his megahit song i took a pill in a pizza. Reporter its hard to believe but just a few hours earlier, this charttopping artist took the subway here, flying totally under the radar. Mike poser in is enjoying Sweet Success right now. But the road here has been anything but smooth. Were here in brooklyn. Were going to check out this vinyl shop. Youve played here before . I have played here before. Did you take a pill anyboin . Ecstasy, i think. I foolishly took a pill, felt like heaven for three hours, felt like hell for 48 hours after a that. I do not recommend that, its a stupid thing to do. . Reporter mike got his first taste of music success at the age of 22 with the breakout . Probably because you think youre cooler than me . A lot of people were saying, you were it, destined for stardom. I had an initial wave of popularity that in time crashed. Reporter over the next four years posner recorded two more albums, both which of were never released by his record label rca. I got shelved. The record label at the time couldnt justify spending the marketing dollars promoting it. It was frustrating because i was making music that wasnt but in hindsight, it was the best thing that ever happened to me. Because i had to learn who i was without being cool, without being popular. Reporter ironically enough two of the songs he wrote for himself during that time ended up becoming massive hits for other artists. Sugar for maroon 5. . Reporter and boyfriend most successful single. . If i was your boyfriend id never let you go . How does it feel to watch Justin Bieber sing your song . Its our song now. He adds his thing to it. He gave it to the world. What was it like working with Justin Bieber . I just thought, this is a really good musician. A good singer, a good guitarist, a good pianist, a good drummer. Hes good at music. Did you learn anything from him . The biggest lesson i took away from just being with him, we toured mystique of fame. Thats when it really wore off for me. I saw what that actually meant. How limiting that can actually be. For people like that, you know, you cant walk out the door. Theres a Million People waiting outside. Reporter so he made a radical decision. I bought this creepy dodge conversion van with a bed in the back. And i thought, what fits in here will be mine, the rest well all the bull [ bleep ] out . . Take off your makeup . Reporter embarking on what he called the ninja tour. His moment to reset, reflect, and rediscover himself as an artist. Were not selling anything, theres no tickets, theres no merch, theres no cds. Theres just guys playing songs. Reporter a stark contrast from the massive stage hes about to own. How would you feel today . Youre about to play at the you get back in your van . I feel awesome. Youd be okay with that . 100 . Reporter but tonight hes closing out the show with the hit song thats brought him back into the spotlight. Its incredibly ironic. Theres a line in the song that says . Im just a singer who already blew his shot . And the writing of that line . Reporter for nightline, im Rebecca Jarvis in brooklyn, new york. Next, strap on your invisible guitar. Were going to rock out at the annual air guitar championships. . Your heart loves omega3s. But theres a difference between the omega3s in fish oil and those in megared krill oil. Unlike fish oil, megared is easily absorbed by your body. Which makes your heart, well, megahappy. Happier still, megared is proven to increase omega3 levels in 30 days. Megared. Excuse me. I think theres a misprint. Oclarence event. D looks right to me. Shouldnt it be clear. Clearly. It is time to get a great deal and a reward card on this turbocharged jetta. Gotta make room for the 2017 models. It is a clarence event. Why is that so hard for people to understand . It seems clar to me. Clear to me. Ready for a test drive . Whatever you want to call it, dont miss the volkswagen model year end event. Hurry in for a 1,000 volkswagen reward card and a five hundred dollar labor day bonus hey, need fast heartburn relief . Try cool mint zantac. It releases a cooling sensation in your mouth and throat. Zantac works in as little as 30 minutes. Nexium can take 24 hours. Try cool mint zantac. No pill relieves heartburn faster. Happy anniversary dinner, darlin can be cleanedlove by a little bit of dawn ultra . Oh yeah. One bottle has the grease cleaning power . Amazing sleep stays with you all day and all night. Sleep number beds with Sleepiq Technology give you the knowledge to adjust for the best sleep ever. The time is now for the biggest sale of the year, where all beds are on sale save 50 on the labor Day Limited Edition bed. Know better sleep. Only at a sleep number store. Ent, strong voice for new hampshire. Narrator then why does kelly ayotte still support donald trump for president . Independent minded republicans across america put principle ahead of party and said no to trump. But not kelly ayotte. She says she still supports trump. Ayotte an independent, strong voice. Narrator if shes so independent, why is she still supporting trump . Disclaimer independence usa pac is responsible with the olympics over we have news tonight from another internationalpe draws elite competitors. The air guitar championships. . Ladies and gentlemen, meet the worlds greatest air guitarist. Its 27yearold matt burns from staten island, also known as aristotle, bringing home the win performing what i like about you and speeding. . The competition now in its 21st thank you for watching abc news. Tune into gma first thing in the morning. Ill be there alongside paula faris. As always were online 24 7 at our Nightline Facebook page and at abcnews. Com. Thanks again for watching and good night. Today on on the Meredith Vieira show. Why everyone is talking about prince williams new do. And next. From the cast of younger, ready to step it up. New make overs you you will not believe. It all starts right now on meredith. . Makes you feel real good. Meredith hey, everybody. We have a great show i was told not to lift my hands up too high because the dress go with with it. Stars of tv land, hillary duff is here. Hillary is here before and lance and i are going headtohead with them in a brand new game. Lets talk about whats hot