adios! thank you, again, guys. [ cheers and applause ] . >> announcer: this is "nightline." >> tonight, north korea showdown. kim jung-un, testing missiles and patience, challenging president trump with threats of nuclear war. >> any message for north korea. >> got to behave. >> reporter: inside a top secret facility in south korea where no camera crew has gone before. with soldiers on high alert. ready to blow north korean missiles out of the sky. plus, healing harry. it's been nearly 20 years since the death of princess diana. now, her youngest son, opening up about his decades of invisible anguish. >> i've probably been very close to a complete breakdown on numerous occasions. >> reporter: why he finally decided to get counseling. and could the one-time party prince, finally be ready to

settle down? what his girlfriend did that is fueling rumors of royal wedding bells. >> reporter: and -- ♪ oh love >> awaking nightmare for li lindsay, went to bed like this, woke up like this. love hurts. and how she solved her terrifying medical mystery. but first the "nightline" five. >> need fast heartburn relief, try zantac, releases cooling sensation in your mouth and throat. works in little as 30 minutes. nexium can take 24 hours. try zantac. >> can a toothpaste do everything well? >> this clean was like, pow. my teeth are glowing. they're so white. >> step one cleans. step two whitens. crest hd, six times cleaning. six times whitening. >> i would switch to crest hd over what i w these are 100% beef burgers that are 100% from denny's. they are 100% made-to-order, which is 100% awesome.

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>> good evening. thank you for joining us. tonight, as the saber rattling intensifies on both sides of the korean peninsula, abc's martha raddatz takes us where cameras have never ventured. a top secret section of a military base near one of the most heavily fortified borders in the world. as north korean dictator kim jung-unthreatens the united states with nuclear weapons, some fear tough talk could provoke a tough talking president trump. ♪ >> reporter: not 4 hours after a show of pageantry and force, and a provocative but failed missile test. ♪ escalating tough talk from north korea with no sign of backing down. >> a nuclear war may breakout at any moment. foreign vice minister telling

the bbc we will be conducting more missile tests on a weekly, monthly and yearly basis. with tensions on the rise, abc news was granted rare access to the men and women on the front lines. everything that is flying right now, these guys are managing? >> yes, ma'am. >> reporter: even as vice president mike pence arrived, visiting the border separating the two koreas, sending a message north across the demilitarized zone. >> the world witnessed the strength and resolve of our new president. north korea would do well not to test his resolve. >> reporter: back in washington donald trump sending a similar message. any message for north korea? >> got to behave. >> reporter: in a less militaryistic venue. all eyes now on the peninsula. and this latest and perhaps biggest foreign policy test for the new american president. >> this is really the first time since 1953 that any u.s. president has, has escalated the

relationship and the tension with north korea to a degree that something has to be resolved. and if north korea pulls the trigger, this is likely target number one. osan air base, just 48 miles from north korea, well within range of kim jung-un's, arsenal of missiles carrying god knows what. a hardened bunker this is serious stuff. >> yes, ma'am, your third set of blast doors here. >> reporter: the first line of defense is always on guard. 24/7. f-16s on constant patrol. anti-missile batteries primed, ready. behind the concrete walls and steel doors, the top secret and rarely seen operations center. on high alert, watching for any north korean missile activity. >> we live with it every day. the nice thing is for my folks, the mission is staring them in the face. >> reporter: they're monitoring the possibility that one day,

one of those missiles could reach as far away as the west coast of the united states. >> once they're able to range and to hit targets within the continental 48, it now becomes an american problem. what used to be a regional or korean problem has now marched across the pacific and become an american problem. >> reporter: there is no doubt osan is within range, the threat is up close, dangerous and continuous. one of the things you sort of sense as soon as you come on base, is how real the threat is. >> absolutely. and what we do here, specifically is we are trained, day in, day out, to be fight tonight ready as we say it. >> reporter: the clowe gain here "fight tonight" you hear it often and always with a since of pride. there aren't many places where i go into, where it says fight tonight in giant letters. that is a little frightening. >> for us, our daily training. we are training at that level to be able to fight tonight.

we don't know when the call is going to come. >> about four stories underground. the operation center is survivable against some high explosive blasts. that's why we are so deep. >> reporter: we visited another top secret facility, the first time ever for a camera crew. if a missile is aimed at south korea, the job here, blow it out of the sky. north korea has conducted five underground nuclear tests in the last ten years. but missile launches are far more common. several this year alone. every one closely monitored on these screens including failed launches. what's it like in here when the ballistic missile is launched? >> well you would thing it would be hectic. but due to the level of training of the soldiers here, actually a pretty, calm exercise. i would compare it to -- to maybe an air traffic controller tower. >> reporter: right next door, rows and rows of bunkbed. if war comes to south korea, the staff will sleep right here. >> reporter: you have food, you have everything you need?

>> the we have food, showers, latrines. >> reporter: lieutenant general thomas burgeonson is deputy commanderen south korea. >> what concerns you most? >> our biggest concern is he is going to miscalculate. our conumber one concern. we want to make it crystal clear to the north korea leadership this would be a few till endeavor were he to challenge this strong, ironclad, bilateral alliance. >> reporter: because we have a new president, and he no doubt, kim jung-un, wants to test him in the same way that dynamic works. is this from your time here from watching here, one of the more dangerous times? >> i would say that there is certainly you can feel the tensions. clearly this is serious. and they need to know that we are prepared and that this, this defensive alliance is strong, and ready to fight tonight. >> part of that defense, patriot

missile batteries. >> notice here in korea we, we keep our launches loaded with live interceptors at all times. so that we are ready to fight tonight. >> reporter: tell me a little bit about the batteries in terms of of what nay can stop, how they stop them, how that works. >> yes, ma'am. well, this weapon system is capable of defeating a wide range of enemy capabilities from unmanned aerial systems to short-range and even long-range ballistic missiles. this battery is, designed to search for detect and engage those inbound ballistic missiles. >> at osan they're confident in the system claiming the success rate of the patriot is nearly 100%. >> it is a bullet on bullet scenario where the patriot missile hits the threat missile and destroys it. >> reporter: far less successful, the recent north

korean missile tests. causing some to speculate the u.s. might be responsible for the rash of missile launch failures bedevilling the north koreans perhaps using cyberwarfare, no proof of that, and no comment from the white house. >> these are delaying tactics. these are not going to stop the north korean missile program, they're not going to stop the nuclear program. >> reporter: a few miles from the patriots on the flight line are the growlers. >> so they have jamming capability, electronic jamming capability. they can deny the enemy ability to launch surface-to-air missiles at our aircraft. >> facing the ever-present threat from north korea, major sean walsh, up in the skies training at least three times a week. often near that prohibited area close to north korea. >> the other night i was up there on monday night, just around sunset. and it's, you get to see the stark contrast. as the lights start to come on, you fly along the dmz, you can look out one window, bright as

day, with the city of seoul and then all of south korea. and then you look out the other side of your cockpit. it is just darkness. >> reporter: make no mistake, it is that darkness which causes concern. the lack of hard intelligence. the unpredictability have created a region on edge. kim jung-un, basically saying he could strike and take out an of the american military bases. could that happen? >> no. no, they could try. but as you saw today, out here, you have air defense artillery brigade, and they have the technology, the capability and they're ready to intercept those kinds of missiles. so they could try. it would be to till. >> reporter: as the the war of words escalates, it's helpful to remember that we have been here before. but as some asia watchers point out, the difference this time, a new and yet to be tested president. >> the south koreans are used to this they have lived in the shat

shadow of the north korean threat for 50, 60, 70ers, not unusual to hear the bellicose remarks. what they're not used to hearing it from the white house. >> reporter: how president trump navigates this latest crisis will be watched and scrutinized closely just as the american forces in osan are watching, waiting, and ready to fight tonight. martha raddatz, for "nightline," in seoul, south korea. ♪ up next, prince harry reveals how seeing a therapist changed his life. and later, it happened in her sleep. the rare and terrifying health hazard that left an ugly wound on a popular contestant from the voice. ♪ the birds the bees and the flowers and the trees ♪ ♪ and the moon up above and a thing called love. ♪ ♪ let me tell you 'bout the stars in the sk♪,

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you know we all know that for years, prince harry was known as the naughty bachelor prince. often landing in the tabloid for his exploits. now he is in a steady relationship showing us his vulnerable side. what led to his drastic life change. here nick watt. >> reporter: prince harry fun one, hell raiser t. party prince. recently, harry has mellowed going stoed with megan markel and we know >> 32-year-old prince unguarded, candid, mildly sweary on a just posted mental health broadcast,

bryony gordon's "mad world." >> it was 20 years of not thinking about it and two years of chaos. >> there has been a terrible accident involve dyingian that princess of wales. >> reporter: his mother, princess diana, the princess without the fairy tale ending died in a car crash in paris, 1997, paparazzi on her tail, a year after her divorce from prince charles. she was 36 years old. the images of william and harry walking behind their mother's coffin, no tears, just stiff upper lips. all around. gives you some idea of how people from that country, from that class, traditionally, deal with loss. >> i can safely say that losing my mum at the age of 12 and therefore shutting down all of my emotions for the last 20 years, has had a quite serious effect on, on not only my personal life but also my work as well. it was described as the party prince, coming out of night clubs. red faced. >> reporter: older brother, quieter william stays home with his seemingly perfect family.

harry struggled. >> we saw that, we witnessed that in his behavior. he was saying he was close to a full mental breakdown. where he was nervous about going, to royal engagements. he didn't really know if he could carry those out. >> reporter: he started dealing with it just a couple years ago. served himself in afghanistan. and worked helping veterans rehabilitate. >> i'm lucky enough to watch some one who should be dead, run the 100 meters. you want definition of inspiration. that is probably it. >> how is the training going? >> going well. >> nice. >> reporter: that work is partly what sparked the personal realization that he also needed help. william, also encouraged him. >> some of the best or easiest people to speak to is a shrink or who ever, i know the americans call them shrinks, you sit down. and you just let it all rip. >> you've done that have you? >> i've done that a couple of times. it was great. can't believe i have never didn't. >> there was a little

nervousness admitting that he sought professional help even then because of the royal family stiff upper lip. >> i actually did a bit of boxing during those two years, i took up boxing. everyone was saying boxing is good for you. really good way of letting out aggression. that really saved me. because i was on the verge of punching some one, so being able to punch someone who had pads was certainly easier. >> reporter: along with kate and william. he launched a charity. heads together. >> just one. >> do this one. >> to tackle mental illness. >> what we're freeing to do is normalize the conversation to the point of where any one can sit down and have a coffee and just go, you know what, i've had a really [ bleep ] day. can i tell you about. everyone needs a hug now and then. and i've been told, i am very good at hugs, giving hugs. fantastic. >> harry speaking to our own robin roberts about his healing process. >> this used to be mum's sitting room. we had to make the decision between the two of us, are we ready to go back into the house

that we grew up in. i'm glad we have. it's like constant reminder, not that we forget. think of her every day. >> reporter: the special life he mentioned he neglected. now been with megan markel of suits fame. long enough that royal watchers are getting all excited about possibly marriage. they reportedly spent this past weekend in tore ron tomorrow where she lives -- toronto where she lives. and according to people she is the plus one for pippa middleton's reception and markel shut down her lifestyle blog. after three about yul years on this adventure time to say good-bye. no reason given. maybe unseemly, to blog if you are intending to marry a prince. >> he is in a great place. in toronto with megan markel, the relationship is going well. he seems emotionally sound. >> reporter: looking back the nearly 20 years to when diana died there was an uncharacteristic, unprecedented reaction from the british public, to diana's death.

scenes outside kensington palace, unbridled mourning for a woman very few new. inside the paris for harry, denial and stoicism. >> my way of dealing with it was stick might head in the sand, refusing to think about my mum, because why would that help? it is only going to make you sad not going to bring her back. >> shows you what an umter nightmare he has had. also the bravery, the courage that he has got to go out and talk publicly about this. so that it helps other people understand their own mental health. >> he is now at the other side, happy, apparently excited to become a father sometime and using his clut to -- his clout. could there be a better way to use royalty, strange celebrity. i'm nick watt for "nightline" in los angeles. >> up next, what did this to megan lindsey's face. "the voice" finalist waking up to nerve pain and a shocking discovery. ♪ ooh love ♪ love hurts

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♪ ♪ you know when peter parker was bitten by a radioactive

spider he got super strength and ajill agility. but when she was bit by a poisonous spider, things got ugly. it's the tough of nightmares, waking up tie a poisonous spider in your bed. >> i had a stinging sensation on my face. i looked on my right hand. i was holding a dead spider. country star and voice runner-up megan lindsey found love isn't the only thing that hurts. ♪ ooh love hurts when she was bitten this february by a rare brown recluse spider. >> it was the craziest thing, for nine days, i woke up. full body rash. pain mine face. night sweats. fever. her face swole.

necrosis seen on instagram. >> i share a lot on line and with my fans. i think when you are that vulnerable you tend to grow. the eternal optimist, lindsay found the silver lining in a scary situation. >> i have gotten really good at covering it with makeup. that's a positive thing. now back on tour, lindsay is grateful to be on the road again. >> i feel like this made me a stronger person. and really endeared me to more people that i could ever have imagined. >> i guess that's what you call a silver lining. thank you fo