different ♪ ♪ i swear when i fall off my feet ♪ ♪ i stare at everything aittle different ♪ this is "nightline." >> tonight, historic steps. over a border and back from the brink. kim jong-un, the first north korean leader to step foot on south korean soil. pledging to end the war. vowing to denuclearize the peninsula ahead of momentous face-to-face talks with president trump. >> this is beyond the united states. it's something that i hope i'm able to do for the world. >> but can the brutal dictator really be trusted? plus, for our lives. stories from the parkland school shooting you haven't seen before. "nightline" spent two and a half months with students who lost friends and loved ones. >> i feel him like laughing when

i laugh. i feel like he's like living through me in a way. >> now turning their anguish into action. and fighting words. >> i don't like your attitude. >> legal eagles nancy grace and dan abrahams duking it out in their crime debate show. is there anything they can agree on? but first the "nightline 5." >> with roomba from i-robot, clean floors can be part your family's everyday routine. unique multi surface brushes remove everything from fine dust to large debris. and even pet hair. and roomba uses a patented dirt detect system that attacks dirt in high-traffic areas of your home. so you can come home to clean floors every day. you and roomba from i-robot. better together. >> number one in just 60

good evening. it was an astonishing display of diplomatic stagecraft as peace broke out on the korean peninsula. with the leaders of north and south pledge pledging to end the korean war. 30,000 americans are still stationed in south korea. now could a meeting between plump and kim jong-un close this painful chapter in history? ♪ an unprecedented moment between leers of two nations still technically at war. >> breaking news overseas. >> reporter: surrounded by a swarm of bodyguards, the usually secretive kim jong-un emerging from the northern side of the dmz. wearing his trademark mao suit, kim walks over, smiling, to the cease-fire line separating north and south korea. for this handshake with south korean president moon jae-in. >> a remarkable summit viewed

live around the globe. >> reporter: kim jong-un simply stepping over the most heavily fortified border in the world. >> you feel the weight of history when you walk or put your toe on that other line. >> reporter: then president moon says, you've come to the south, when can i come to the north? and kim jong-un says, why don't you try now? >> oh, they're holding hands. >> he went back into the north, look at that, almost as if they're erasing the line. >> reporter: a ceremonial honor guard noting 5,000 years of shared korean culture. but there was also laughter. kim jong-un turning his nuclear tests into a punch line. "i won't interrupt your sleep anymore with early morning missile tests," he said. the two men so different seemed to enjoy it all, chatting among the trees, on a picnic bench alone, for almost 45 minutes. introducing their wives, kim jong-un's wife all smiles. the two leaders promising to sign a peace treaty this year

formally ending the korean war, pledging the denuclearization of the peninsula. arms raised in triumph. then an awkward embrace. afterwards kim jong-un stepping out onto the world stage as a statesman for the first time. saying, we are one nation and cannot be separated, we are one blood. with that promise of peace, north korea also agreeing to diplomatic talks with the u.s. it will be the first time any sitting u.s. president will meet with a north korean leader. >> things have changed very radically from a few months ago. you know the name-calling and a lot of other things. they're treating us with great respect. >> reporter: it's an astonishing turn of events. just this past july, north korea tested an intercontinental ballistic missile, going higher and farther than ever before. kim jong-un called it a fourth of july gift to the trump administration. >> north korea best not make any more threats to the united

states. they will be met with fire and fury like the world has never seen. >> reporter: the u.s. intelligence analysts believed north korea had produced a nuclear warhead with the capability of reaching the u.s. mainland. >> we will have no choice but to totally destroy north korea. rocket man is on a suicide mission for himself and for his regime. >> reporter: when we visited the port city of pusan, we noticed president trump's heated rhetoric had everyday koreans on edge. robert kelly teaches politics here in pusan, talking about the risks of nuclear armageddon. >> so the idea is that, i'm holding a gun to your head, you're holding a gun to my head, as long as we both don't pull the trigger, we're both okay. >> that's classic arms control, brinksmanship. >> yeah, it's nuclear

deterrence. >> reporter: a delicate balance of power with neighboring countries like china too. abc's bob woodruff traveled over 800 miles along the border. >> this farm barrier right here, that is north korea. >> are you afraid of these nuclear bombs that kim jong-un is developing? yeah, very dangerous. you're worried about it. yeah, very dangerous. yeah, yeah. what do you think we can do about it? can we stop him from doing this? >> peaceful solution. peaceful solution. >> reporter: but this year a pathway to peace opened up at the winter olympics in pyeongchang with the newly elected south korean leader, the two koreas agreeing to field a joint women's hockey team for the winter olympics. and the president who once said negotiating with north korea was a waste of time accepts the offer. >> the speed of this is quite extraordinary. and people are especially concerned. because donald trump would

pushback. he's unlike anybody else who's ever dealt with a north korean leader. maybe in the end that's what brought them together. >> reporter: it will be a delicate truce if history is any guide, trusting the north korean regime can be a risky propositi proposition. >> even if president trump sits down and the north koreans promise to denuclearize, we are a long, long way from knowing whether they will actually do that. >> reporter: kim jong-un stands accused of starving his own people, brutally executing and torturing members of his own family and inner circle for disagreeing with his policies. >> it's a gulag. there's massive human rights violations. people are starving. there's a whole effort that needs to happen. >> you really have to remember what's going on inside that country and what he's been responsible for. i cannot look at him without inking of otto warmer. >>eporter:22-year-old american otto warmbier was detained in north korea in 2016, accused of stealing a propaganda

poster and sentenced to 15 years' hard labor. >> please save my life, please think of my family. >> reporter: the north koreans returned him to the u.s. in june of last year after warmbier suffered a brain injury and fell into a coma. >> their son, who was just returned from north korea with severe brain damage, has now died. >> reporter: north korean officials denied cruelty saying, we provided him with medical treatment and care with all sincerity on a humanitarian basis until his return to the u.s." yesterday warmbier's parents filed a lawsuit against the government of north korea alleging their son was brutally tortured and murdered by kim jong-un's criminal regime during 17 months of captivity. >> it's a brutal regime. and we'll be able to handle it. >> reporter: perhaps prematurely, many have credited president trump with ending this nuclear standoff. there's even talk of a nobel peace prize. >> i think the responsibility has fallen on the shoulders of the president of the united

states. and i think we have -- i think i have a responsibility to see if i can do it. >> president trump was handed the worst cards in the north korean situation of any president before him. all the presidents before him who were negotiating did not have a north korea that was capable or very close to being capable of launching a missile with a nuclear warhead. >> reporter: it's been more than 60 years since the cease-fire in a war that cost hundreds of thousands of lives on both sides. it's unclear if this truce will pass the test of time. up next, intimate moments with florida school shooting survivors who lost their closest friends. >> i've never cried like that in my life. ally pretty. surprised? it's called always discreet boutique. it looks and fits like my underwear.

i know what you're thinking. how can something this pretty protect? hidden inside is a super absorbent core that quickly turns liquid to gel... ...for incredible protection. so i feel protected... ...and pretty. always discreet boutique. poallergies?reather. stuffy nose? can't sleep? take that. a breathe right nasal strip instantly opens your nose up to 38% more than allergy medicine alone. shut your mouth and say goodnight, mouthbreathers. breathe right.

with roomba from irobot, clean floors can be part of your family's everyday routine. roomba's two unique multi-surface brushes grab and remove everything from fine dust to large debris and even pet hair. and roomba uses a patented dirt detect™ system that attacks dirt in high-traffic areas of your home. so you can come home to clean floors everyday. you and roomba from irobot. better together. i knew at that exact moment ... i'm beating this. my main focus was to find a team of doctors. it's not just picking a surgeon, it's picking the care team and feeling secure in where you are. visit cancercenter.com/breast

♪ from the very first days after the shooting at marjory stoneman douglas high school, "nightline" has been following six survivors through the healing process. finding their voices in realtime. and becoming accidental activists in front of our cameras. tonight we present just a small piece of our upcoming documentary. >> 911, what is your emergency? [ gunfire ] >> someone was hunting my classmates. >> marjory stoneman douglas high school is being shoot up. >> being shot up? >> everyone on the floor, on the floor! >> my whole future was wiped out.

>> as every day passes, it feels like i'm farther away from him. >> i want people to understand what i witnessed that day. >> i've never cried like that in my life. >> going pack to normal was not possible. >> make sure that no kid ever has to see what i have to see. >> we're still not safe. >> we just want what will make our country safer, you know? >> never again, never again! >> we're the activists of this movement that's growing. >> me and dylan rushed over and met up with joaquin's family and we waited. >> we were there for hours. just like waiting. praying. and like -- it was just it was a was a lot, seeing all the people

who were crying. i was like, it's not going to be us, he's okay, he's somewhere. >> all i kept thinking in my head was, please be safe, please be safe. over and over. >> one of the 17 lives lost. joaquin oliver. >> i've never cried like that in my life. yeah. it was really hard. >> thought it was all a dream. i woke up the next day thinking i wanted to text him or something. then just couldn't. >> it was kind of like my whole future was just like wiped out. we just like clicked right away. like kind of corny, like love at first sight, but i swear, i

swear. joaquin showed up. and he sat in front of me. i just remember being so nervous. to be so close to him, touching his face was like, oh my god. and i just remember like melting immediately. because anyone who sees that video sees the way he looked at me. it was like -- unreal, you know? i feel him. like laughing when i laugh. i feel like he's like living through me in a way. like that's how close we are. i feel it. the connection is still there. you know? i feel him all the time. >> i knew him since he first moved to florida. because we went to the same preschool together. it was somebody i talked to every day, about everything. he's always been like the light in the room.

>> he was so comfortable in his own skin. he was just glowing all the time. everyone wanted to be just like him, you know? we loved like there was no tomorrow. until there was no tomorrow. and i'll always be thankful for that. >> what's your personal stance on assault-style weapons like ar-15? >> it's a head scratcher, where we are. sot's going to be -- it's going be a debate. i've always defended people's right to defend themselves. >> with an ar-15? >> i haven't got specifics. >> we want commonsense gun laws. we want privatized selling to be completely reformed so you can't

just walk into a building with $130 and walk out with an ar-15. >> today marks the one-month anniversary of when the shooting happened. so we're going to have 17 minutes of silence at the football field of my high school. i want to make sure that no kid my age ever has to see what i have to see. >> what time's the walkout? >> it starts at 10:00. >> okay. >> students across the country, around the world, walking out of their schools this morning. >> protests are beginning. >> kids, not guns! kids, not guns! we want change, we want change! >> hundreds of thousands of students are calling for gun control. >> kids at over 3,000 schools are involved.

>> i don't really know what's going on, so we're just going to wing it, i guess. >> i'm here for joaquin. i'm here for every other kid and their safety. >> you can watch them turn their pain into activism in the documentary "for our lives: parkland" which will air on freeform on monday night, 10/9 central. they're the best of enemies. nancy grace and dan abrahams facing off on their new crime show. so, what's new? we just switched to geico and got more. more? they've been saving folks money for over 75 years.

a company you can trust. geico even helped us with homeowners insurance. more sounds great. gotta love more... right, honey? yeah! geico. expect great savings and a whole lot more. the world is full of different hair. that's why pantene, the world's #1 conditioner brand, has conditioners for every hair type. from air-light foam for fine hair, to nourishing 3 minute miracle for thick and curly. and the moisture-infusing gold series collection. giving more women great hair days - every day. pantene. world's number one... conditioner brand.

♪ ♪ get high speed internet from at&t. $30 per month. no extra monthly fees. more for your thing. that's our thing. visit att.com/internet.

♪ finally tonight, they're two highly opinionated lawyers going toe to toe, and you're the jury. >> none of his story in my mind fits together -- >> reporter: when the topic is crime -- >> can we agree on something? >> reporter: nobody gets more

fired up than nancy grace -- >> how much do you know about kayaks? >> i have kayaked many times. >> reporter: and nancy. now they're taking their legal riffs and turning them into a tv show, "grace versus arbams." >> you met during the "court tv" days. when did you know you had that on-air spark if not chemistry? >> the kind of chemistry that comes out of a lab? >> somewhere out there the devil is dance tonight. >> reporter: nancy a former prosecutor turned legal analyst. >> good evening and thanks for joining us. >> reporter: dan is my former coanchor and abc news chief legal analyst. the duo focusing their legal expert tease on high-profile trials that have captivated america, from casey anthony -- >> forget about chloroform, how to make it, how to use it, that means nothing to you? >> yes -- >> reporter: to scott peterson.

>> i think he's guilty. >> i think he's guiltier. >> reporter: grabbing every headline you can imagine. one of the stories is the serial story of adnan syed -- >> convicted in 2000 for the murder of his ex-girlfriend. >> this is a global link prepaid call from -- >> reporter: the case reaching pop culture status after it was featured in the hit podcast "serial." "nightline" was behind the scenes during the show's taping. >> i think adnan syed is guilty, i do not believe he deserves a re trial. >> dan, you see reasonable doubt? >> i think the reason the show was so compelling is there is reasonable doubt. >> oh, lord, here it comes. >> you clearly have an on-air love/hate relationship, yet off-air i feel you guys like each other and dare i day respect each other? >> i'm taking the fifth.

>> you know, like and respect, you know -- >> they begrudgingly respect each other, but don't tell them i told you. thanks for watching "nightline." as always we're online at our "nightline" facebook page. good night, america. have a great weekend.

we need to help more tocalifornians get ahead.d, that's why antonio villaraigosa brought both parties together to balance the state budget with record investments in public schools... and new career training programs.