>> jimmy: this is "nightline." >> tonight, breaking news. national security adviser michael flynn resigning after reports that he misled trump administration officials about conversations with a russian ambassador. what he wrote in his resignation letter and why he apologized to president trump and vice president pence. plus water park nightmare. parents of a young boy killed on the world's tallest water slide speaking out. >> it's my son dead. >> what went wrong and as these thrill-seeking rides are getting more extreme is there a way to tell how safe they are? and making metal. behind the scenes with metallica. hotter than ever. their brand-that you performance with lady gaga that didn't quite go as planned.

exclusive details about the band's private dynamic. and a lesson from the master on the band's famous crab pole -- >> i'm a 43-year-old man in tight jeans, i'm not sure this is going to happen. >> first the "nightline 5." >> we enjoy life by enjoying it. >> boost simply complete. made with nine ingredients, 25 vitamins and the minerals, 10 grams of protein. boost, be up for it. mom's got this cold. stuffy nose, no sleep, mouth breather. just put on a breathe right strip. it instantly opens your nose up to 38% more than cold medicine alone. shut your mouth and say good night, mouth breathers. breathe right. >> number one in just 60 seconds.

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good evening. thanks for joining us. we begin with breaking news. donald trump's national security adviser michael flynn has resigned tonight, just one month into his tenure, amid growing concerns about his contact with the russian ambassador and whether he misled vice president pence about whether sanctions against russia were discussed. flynn wrote in his resignation letter, "unfortunately because of the fast pace of events i inadvertently briefed the vice president elect and others with incomplete information regarding my phone calls with the russian ambassador." the retired lieutenant general added "i have sincerely apologized to the president and vice president and they have accepted my apology." we'll have a complete wrap-up on "good morning america" tomorrow. a tragic story, we're hearing from the parents of the boy killed on that extreme water slide billed as the world's largest. their emotional and candid account of the unimaginable. matt gutman sat down with the family who has a message for us all. >> reporter: on

the schwabs went to the world's tallest water slide, admission was free for the families of state legislators. but that thrill ride would cost the kansas state let gislator a his wife most dear. >> six went to the park and five came back. >> reporter: for the first time scott and michelle schwab recount that tortured sunday. hoping that sharing their story will help keep caleb's memory alive. >> i still remember him sitting on the floor, we're going to go to the park! he lit up, so excited. >> reporter: the schwabs piled their four boys, including 10-year-old caleb, into the car. they had a nickname for their second son. >> called him monkey bear because he climbed everything. he would hug like a bear. he's 10 years old, he still wraps his arms and legs around you for a hug. >> reporter: he was that kind of brother. you see him here dancing with his baby brother isaac. when they got to the park, caleb and his 12-year-old brother

nathan went right to the 170-foot scaffold of verruct, which means "insane" in german, billed as an extreme thrill ride. >> i said, brothers stick together. he says, i know, dad. >> reporter: it was the last time his parents would see caleb alive. big brother nathan was dutifully waiting for him at the bottom when the unimaginable happened. >> he was screaming. he flew from verrukt. >> reporter: nathan ran to find his mother but the horror made it nearly impossible for the 12-year-old to explain. >> there was a gentleman who wouldn't allow me to come close enough to see what was going on. he just kept saying, "no, trust me, you don't want to go any further." >> reporter: scott was in such shock, good samaritans had to confirm the incomprehensible. >> i need to hear you say it, is my son dead? he said, yes, your son i

put us on a golf cart, sorry you lost your son. it was surreal. i hardly remember driving home. >> reporter: so far no criminal charges have been filed, but the family has settled with the theme park for an undisclosed sum which will go to caleb's three brothers. the family is still pursuing legal action against others including the firm contracted to build the slide. they declined our request for comment. >> they call it an accident. but i think you and your attorneys believe that negligence caused this accident. >> yeah, yeah, it's an accident but there's an accounting because someone was negligent. >> reporter: in a statement to abc news, the park said it was heartbroken over the tragedy and the safety of our staff and our guests is our top priority. the park's verrukt water slide set to be torn down. this is the view from the top of verrukt. thrill-seekers fall 17 stories in send

nearly 70 miles an hour. commercials for the ride even asking -- >> are you insane? >> when the ride first opened three years ago, many were asking a different question. is it safe? concerns only heightened after this video from the ride's testing phase appeared on the travel channel show "extreme water parks." sandbag dumb he's launching off the slide. the ride's opening was repeatedly delayed while designers attempted to work out the kinks, adding in more safety features like netting and safety belts. when it opened it was finally deemed a feat of engineering. i was the first tv journalist to go down. >> literally not for the faint of heart. >> reporter: lifeguards, safety checks, and on this day at least, a park employee at the top of the ride reading a two-page liability agreement. >> there's a risk inherent to the activity -- >> reporter: my first trip down was a vertigo-inducing plummet, but overall fun. a complety

than the tragedy that unfolded when caleb schwab lost his life. but it's easy to see how in a fast-paced ride like this, things can go wrong in an instant. this man was in an austin, texas, slide when he ka reared off the edge, falling down a rocky cliff. he suffered a broken arm and fractured ribs but survived. in this video a man desperately holds on to another rider. after falling off of the raft before eventually being plucked back to safety. >> i've got three kids that tale from the ferris wheel. >> reporter: last august three girls were injured when they fell off the ferris wheel in green county fair, tennessee. last april in texas a teen died at a church carnival. she was hurled from her seat on a small spinning ride like this one. there nor federal regulations governing amusement parks and the enforcement of state laws is patchwork. the schwabs and their lawyers are trying to change that.

but sustaining themselves on faith and friends. ♪ >> reporter: at caleb's funeral his baseball team huddling with scott. and it was scott's friends who a few months after that funeral took him on a retreat and forced him to spend time grappling with his grief. >> after caleb was killed, you penned a letter to him. >> they gave me a notebook, pen. said, hang out by the river and write a letter to your son, then you need to write the response. so my heart had to say what i never really got the chance to say. it was hard. but it was a release. >> reporter: caleb's brothers keep going by keeping their brother in their minds. watching those videos. some of them how-to movies he shot himself. >> so in order to push that button in, we need to take this thing out. and that's kind of the key hole. >> reporter: and that one of him cradling his little brother.

at that now. then there's other times you can't sleep, you want to look at it. >> what do you miss most about caleb? >> giving him hugs. >> hugs. >> hearing about his day. >> my morning hug. >> watching him play soccer. >> why was it important for you to do this interview? >> we have a box of greeting cards from around the world. we just want people to know we're thankful. yeah, we're still hurting, but we're going to be okay. >> reporter: for "nightline" i'm matt gutman in kansas city. up next, just how did metallica get hooked up with lady gaga for the grammys? we're behind the scenes with the band. ♪ coming back a symptoms kept on my long-term control medicine. i talked to my doctor and found a missing piece in my asthma treatment with breo. once-daily breo prevents asthma symptoms. breo is for adults

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so if you've had the privilege of hearing their dead growls in concert, you might be surprised to learn the members of metal car level-headed family men offstage. they've dominated the heavy melt scene over three decades. one of their keys to longevity, they say, is finding work/life balance. downright zen heavy metal. here's abc's nick watt. ♪ >> reporter: they even shared a mike. after a tech mishap, gaga and metallica rocking the grammys. how did this happen? >> gaga has been a sort of self-professed metalhead, life-long metallica fan. we were at dinner six weeks

and i said, we're doing the grammys, would you like to join? she said yes. it took about 12 seconds. >> reporter: we were granted exclusive access to a preshow practice in l.a. friday night. ♪ you guys and gaga. didn't immediately strike me as a natural marriage. >> by the time she spent, what, like 30, 45 minutes with us, she totally got into the song, worked out vocal arrangement with james, got the feel of the song. >> it was pretty seamless. ♪ my poker face >> reporter: gaga i'm familiar with, we know "poker face" among others, a worldwide number one. she played the super bowl halftime show. ♪ but these guys? yeah, i've heard "nothing else matters." ♪ and nothing else matters

♪ never cared what they do >> i'm going to come clean. i'm more of a fleetwood mac kind of guy. i finally understood what your kind of music is about because you can feel it. and -- >> without a doubt. >> it was kind of eye-opening for me. >> you kind of enjoyed it. >> i did enjoy it. >> see, that's the thing. our message comes by or comes through most accurately, most precisely, when you see us in a live situation. >> reporter: we all know who metallica are. i mean, you can buy a t-shirt at h and m. as for "sand man" -- ♪ possibly the biggest metallica number. now i need to know more. >> i started this band when i was 17. james and i have been together for 35 years. it's the longest relationship i've had with anybody, basically, other than my father. >> reporter: james hatchfield leads

100 million-plus album sales later, after massive tours on every continent, eight grammys, they're still here, bigger than ever. today they announced a north american stadium tour. >> now we sit here in our early 50s and go, wow. this is really cool. they keep coming. >> reporter: in just a few months they've sold nearly 1 million copies of "hardwired to self-destruct" and over 36 years have, well, not self-destructed. you guys are still playing the grammys. you guys are still selling out stadiums. you're still number one. >> it's very honest, what we do. we strap on our instruments, the four of us, what you see is what you get. ♪ >> reporter: this all might never have happened. he came to the u.s. in 1979 from his native denmark to become a tennis player. >> the black sheep of the tennis side of the family because my father was a professional tennis player.

passion, my hobby, waiting in the wings to take over, and it did. >> reporter: james hatfield answered a want ad for other metal musicians to jam with. >> when james and i started, i was my mom. i never said that before. that's an exclusive on "nightline." >> you never want to play stiff. sometimes we look stiff. ♪ >> i love the facial expressions, nice. >> so you look like you're pissed off, you look stiff. but actually, you're just bringing more impact to the strings. that's the way i look at it. >> reporter: bassist rob trujillo has become famous for his crab pose on stage. i'm a 43-year-old man in tight jeans, i'm not sure this is going to happen. >> you always got to make sure your pants are up. pull your pants up. then you kind h

♪ >> i can't. >> reporter: it's really about more than just the music. >> i love playing drums. but i love playing drums in a collective. drumming's the gateway to the adventure. i'm not one of these guys that sits around, plays drums for eight hours, always has to tap on something. >> reporter: 2004, "fly on the wall" documentary "some kind of monster" showed a band with some issues. >> i was straight up with you, i told you, [ bleep ]. what have you been doing? >> a bunch of guys who have never really had an in-depth conversation about how they're feeling, what's going on, what they think of everything around them over 25 years. all of a sudden it happens. all hell breaks loose. >> reporter: these days they slow down to smell the coffee. >> we don't tour for more than two weeks. we have a very strict two-week

care of our families, wives, domestic responsibilities. then we get a chance to run away with a rock 'n' roll band. >> reporter: coming to a stadium near you again this summer. >> it's pretty crazy that people still, 35, 36 years into a career, come, still care, still are passionate, and that there's still a turnover for newer, younger fans. >> why do you think people still care and support you? >> hard to answer that without -- i sometimes get a little uncomfortable, sort of hand on heart. we're somewhat good at what we do. ♪ >> reporter: near doesn >> reporter: niche doesn't describe duetting with gaga at the grammys, but hey. nick watt for "nightline" in los angeles. up next, "send my love" singer adele requesting a do-over at the grammys. whyhe

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finally, as adele might say, if at first you don't succeed, try, try again. ♪ hello >> adele opened the gram he's with her signature greeting singing "hello." from there on it was her night. but it was the british songstress' tribute to the late george michael that stole the show. as she began a gripping performance of michael's "fast love," adele paused and dropped an f-bomb. >> i know it's [ bleep ], i'm sorry, i can't mess this up. >> this isn't the first time a high-profile artist has had to stop amidst a high-stakes performance. patty smith taking a pau

at the nobel prize ceremony in stockholm this past december. >> i apologize. sorry i'm so nervous. >> mariah carey's new year's rocking eve disaster which certainly didn't end as well. yesterday's hiccup didn't stop the superstar's momentum. capping off the evening by by accepting her fifth and final grammy of the night for album of the year. >> as you can see, it took an army to make me strong and willing again. and to do it. and i thank you all from the bottom of my heart. >> but her acceptance speech was flawless. thanks for watching abc news, and as always, we're online at abcnews.com and our "nightline" facebook page. good night, america.

>> you know, some people say it takes money to make money. but around here, it just takes guts, brains, and nerves of steel. does one of our players today have the right stuff? we're about to find out. let's play "who wants to be a millionaire." [dramatic music] ♪ welcome to "who wants to be a millionaire." you guys ready to go today?

all right. from playing pinball to running marathons, our first contestant lives and breathes competition. she's without a doubt ready to compete against our 14 questions. from chicago, illinois, please welcome liz greenwood. ♪ hey, liz. >> hi. it's good to meet you. >> come on over. ♪ welcome to "millionaire." >> thank you. >> um, pinball? >> yes. >> that's a throwback. >> [laughing] it's big in chicago. i'm on an intramural pinball team called the pin pals. >> wait, stop. there's such a thing as an intramural pinball... league? >> yes. >> and you're on a--what's the-- what's the size of this team? >> uh, it's about 8-- 8 to 10 people. >> there's 8 or 10, and y'all are called the pin pals? >> yep. >> that's--i did not know that pinball was still a thing. >> oh, yeah. >> that's amazing. >> mm-hmm. >> i don't even know what questions to ask that would be even remotely... how's the tilt thing going? >> [laughing