this is "nightline." >> tonight, sex, drugs and allegations. he's the man behind hits for britney, katy and kelly. bull now kesha is accusing producer dr. luke fof abusing hr for years. even a sexual assault. >> we're asking here time to stop abusing her. >> but he denies it. and in the past, the singer told us he was one of her best friends. >> he's like a protective older brother. >> so, what lead to her change of tune? plus, free ride. forl get the tour de france. here in mexico city, the ultimate bike race has no course, no officials, not even prize money. the alley cats compete for only bragging rights, and they're willing to risk their lives. and, it's story time. from kerry washington to jessica

alba and even kate middleton. fashion royalty wear tory burch. tonight, she reveals how she elevated flats to high style. >> this was the first classic shoe. >> and became a billionaire doing it. but first, the "nightline" five. >> you, my friend, are a master of diversify case. who would have thought that three cheese lasagna would go with chocolate cake? the same guy that thought that small caps and bond funds gould with emerging markets. it's a masterpiece. >> thanks. >> clearly, you are tiype e. you have made it, phil. what's our strategy with the fondue? >> diversifying your portfolio? e-trade gives you the tools and resources to get it right. are you type e? >> number one in just 60 seconds.

good evening and thanks for joining us. it's a bomb shell lawsuit filed by pop star kesha against her long-time producer. alleging that dr. luke, as he's known, constantly insult ltd her, harassed her and even sexually assaulted her. he'sdynying the claims and suing her back. but now, come meants kesha made right here on this broadcast could end up having a big impact on the case. kesha. known for those pop hits that burn up the charts. songs that are hard to forget. like "timber." ♪ it's going down ♪ i'm yelling timber >> reporter: but yesterday, she was in the spotlight for a far more serious matter. alleging abuse, emotional, verbal and even sexual, by her long-time producer, dr. luke. >> we're asking for him to stop abusing her. >> reporter: mark geragos is kesha's attorney. >> there's one incident where she's afraid that he's going to strike her.

>> reporter: dr. luke's real name is lucas got wall. if you haven't heard of him, you have heard his hits. from "since you been gone" to "roar." he's one of the most successful music producers of our time. but now, in a new lawsuit, kesha's making an explosive claim. that he sexually assaulted her. >> the ghb date rape drug allegation is extremely disturbing. >> reporter: tell us about that. >> he has her take a, what he calls a sober pill. next thing she knows, she wakes up naked in his bed the next day sore and knows that she's been violated. >> reporter: that's a serious allegation. why not take it to the police first? >> a lot of this stuff put her in a situation psychologically where she couldn't face it. >> reporter: she says that in addition to the sexual abuse, dr. luke forced her to drink and

do drugs. all this, plus constant e motional abuse. he allegedly called her a fat expletive refrigerator. led her, she says, to develop a potentially fatal eating disorder. kesha was admitted to rehab earlier this year. did dr. luke have anything to do with that? >> yeah, dr. luke in many ways was the cause of her getting to the point where she had to go to rehab. >> reporter: this is allegedly been going on for ten years. why file the lawsuit now? >> that's what's so kind of ironic about it. the fact that he drove her to the brink of death, the fact that she's had to go through all this therapy has finally taken her to a place where she's strong enough to be able to do it. >> reporter: for almost ten years, since she was just 18, kesha and dr. luke created dozens of hits together. like -- >> inside we are who we are ♪ >> reporter: and they're still bound by a contract to this day. and that is what dr. luke says this is all about. a statement released by his lawyer says, "this is an attempt

to extort dr. luke into releasing kesha from her exclusive recording agreement." his lawyers immediately filed a countersuit for defamation and breach of contract. dr. luke's claim is that this is all just an effort to get her out of her contract with him. any truth to that? >> well, get her out of the contract, get her out of a predatory abusive relationship. >> reporter: but when kesha spoke to chris connell loin "nightline" in 2011, she had nothing but praise, even admiration, for the man who discovered her. >> he believed in me when nobody else did. >> reporter: she and her mother were living a much more simple life. hosting paris hilton and any come ritchie on their reality show. >> like to dance? can you show us? >> reporter: around this time in 2005, dr. luke found kesha in nashville, tennessee. chef was a high school student,

trying to break into the entertainment business. >> she moved out here and she was sort of sleeping on people's couches and stuff like that. she worked around for, you know, wrote a lot and got it together. >> reporter: but according to kesha's suit, dr. luke convinced her to drop out of high school, leave her life behind and move to los angeles. and then, she says, he neglected her and her career for years. in what she calls a glaring example, remember the 2009 flo-rida song "right round?" well, that's kesha singing. she claims in her lawsuit, she never saw a dime. >> she was the hook girl on that song. the hook girl dunce always, in fact, mostly doesn't get credit on the song. ♪ you spin my head right round >> you get paid for a day or two of work. >> reporter: it wasn't until the following year that her career took off with the runaway hit "tik tock." ♪ the party don't stop >> the album sold

extraordinarily well on the power of that single. and she was an artist who broke off of a hit single. >> reporter: three years ago, dr.vited us into his los angeles studio where he and kesha made the music fans can't get enough of. >> was the vibe different because she had gotten over as an artist, because she had a hit? >> in some good ways, yes, like, she seemed to grow into it a little bit more. and, you know, certain kind of experience you get from going through all this, that can make you grow. as a person. >> reporter: and back then, kesha told "nightline" that during those long hit-making sessions, the two became very close. >> i call him, like, every day about all my problems, honestly. he's one of my best friends and

he's like a brother and -- >> boys? >> oh, yeah, oh, yeah. he knows about everything. i'm not, like, really one to keep my secrets, so, i tell him everything anyways. >> the claims that she made about 245their close, relation i think, is a double-edged sword. i think that's going to hurt her claim, because it's going to be hard to explain, why would you say all those wonderful things about your rapist? on the other hand, explaining a cycle of abuse to a jury involves how, very often, victims cover for their rapist. >> reporter: the question now? will any other stars who worked with dr. luke claim they were victims, too? dr. luke has worked with some of the biggest names in the industry. kelly clarkson, britney spears, katy perry. are they going to come forward and support kesha in this lawsuit? >> well, they certainly haven't come forward and support dr. luke, have they?

i haven't seen, in fact, it's been quite the opposite. >> reporter: now a jury may have to determine as their song says -- ♪ we are who we are >> reporter: whether kesha and dr. luke really are who they say they are. next, a group of hard core biker dudes competing in a race that puts the tour de france to shame. and later on "nightline," tory burch made flats fancy. now everyone from anne hathaway to kerry washington is sporting her designs. oh, and she's a billionaire. i'm angela, and moking with chantix. people who know me, to this day they say, "i never thought you would quit." you know, i really didn't either but chantix helped me do it. along with support, chantix (varenicline) is proven to help people quit smoking. it gave me the power to overcome the urge to smoke. some people had changes in behavior, thinking or mood, hostility, agitation, depressed mood and suicidal thoughts or actions while taking or after stopping chantix.

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you're about to meet a group of adrenaline junky bikers so hard core, they make the tour de france look like a practice run. on this race, there's no course, just chaotic streets and nerves of steel. abc's mariana van zeller went along for a hair-raising ride. >> reporter: we're in mexico city, riding in one of the craziest bike races you've ever seen. there's few rules here. no set race course. and certaininly no officials closing down the streets. making cars and pedestrians fair game. dubbed alley cats, these illegal races are the invention of bike mes sjengers. "nightline" got a special invitation to go inside this punk rock tour de france. to see what compels these guys

to risk life and limb for mere bragging rights. getting onto a motorbike right now. >> what do you think of this guy? >> loco. >> reporter: look at him. look at him. meet lucas, the king of the alley cats. who, with his homemade helmet cam in towel has been traveling around the world, filming these races for more than a decade. he asked to be interviews where he's most comfortable. >> yeah, this is great. it's like really comfortable. >> reporter: what happened there? >> well, just avoiding potholes. it's mexico. >> reporter: lucas once competed in organized bike racing. the type that occurs on closed courses without speeding traffic or blown red lights. but always the rebel, he felt constrained by the rules. he quit.

and soon fell in love with the alley cat race. huh does it feel to be so close to danger all the time? >> feels good. you know, i'm familiar with danger. you have a buzz with your mind, saying, you know, i'm not totally in control of what's going on right now. >> reporter: on race day, we meet up with lucas and some of the other top riders. >> bit nervous. >> reporter: chris from new york city, considered one of the fastest in the world. and pancho, one of the best mexico city riders. ready? >> think so. >> reporter: he's not nervous. i'm nervous for him. he says i'm getting him nervous just by talking like this. >> we are starting very soon. >> reporter: organized to mimic a day of delivers packages, the race is made up of a series of checkpoints scattered throughout the city. racing in teams of two, riders

much check in at each location before heading to the finish. >> woo! ♪ >> reporter: this is some crazy stuff. oh, my god. oh, my god. even though we're on bikes, it is almost impossible to keep up with these guys. and some of the maneuvers we're doing here are, like, crazy dangerous. oh, my god. in 2008, an alley cat rider in chicago ran a red light and was struck and killed by an suv. it's the only known death attributed to an alley cat. >> people watching the video might say, my god, these guys are on the verge of killing somebody or whatever, but it's just the opposite.

99.9% of accidents are not caused bid us. >> reporter: i totally get your point. there is the idea, though, that there's not a lot of respect for traffic. >> incidents are rare. but as far as breaking laws, i mean, that's like every 30 seconds, you know, or less, i mean -- >> reporter: that's what you guys do. >> get off! use your head. >> reporter: back in the race, the riders are finding the checkpoints as they go. their race directions are stamped at each stop to prove that they were there. but even finding the checkpoints is an immense challenge in this crowded city. chris, lucas and poncho are lost. they end up in this sprawling marketplace. finally, we catch up with lucas

and the other riders, but our path is suddenly blocked by a massive highway. lucas just hops off his bike and playing crossing guard, holding his hand out while well scurry across six lanes of traffic. chris and krponcho arrive at on of the checkpoints. they do not complete a task. they were supposed to take a cell phone photo with their teammate. >> ay, yi, yi. >> reporter:t's now a mad dash to the finish. usa versus mexico. with his legs spent, poncho eagerly hops a ride. this puts chris just out of reach. poncho beats chris and lucas to the finish. but it doesn't even matter, as chris finds out he's been disqualified. >> this is why i asked in the

beginning in english what the rules are, you told me something different. [ bleep ] idiots. >> reporter: how was it? >> it was intense. >> reporter: it was a crazy rush for us just to be following on motorbikes. i understand why you guys like doing this, crazy adrenaline. >> at the beginning, it was really dicey, but going through the market, that was crazy. and then going on the back roads, like, just -- real mexico. >> reporter: except for some bumps, bruises and flat tires, these alley caters have survived to race another day. for "nightline," i'm mariana van zeller in mexico city. next, oprah may have put tory burch on the map, but now she's so famous, she plays herself on shows like "gossip girl." tonight, the self-made billionaire reveals how she brought flats to new heights and came out on top.

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billionaire designer tory burch has conquered the fashion world and the business world. so, what's the challenge she still continue frofronts daefrs? she reveals her secrets to abc's amy robach. >> reporter: she is one of the biggest forces in american fashion. designer tory burch. known for her line of affordable yet loux rouse items that helped propel her onto the red carpet with a slew of celebrity fans, like jessica alba, kerry washington and kate middleton frequently spotted sporting her line.

you have a lot of star power associated with who is wearing you. >> it's funny. i never actively per sued people. i always wanted them to -- it to be organic and wanted them to wear it. >> reporter: her designs appearing on television shows like "gossip girl." >> last season's tory burch glasses. >> reporter: all branded with that iconic double t. >> got them on sale. >> reporter: her business booming. forbes calling her the second-youngest self-made female billionaire in america. named on forbes 100 most powerful women list. >> i'm flattered and surprised. >> reporter: that early on endorsement in 2005 from oprah winfrey certainly didn't hurt. >> people are calling tory burch the next big thing. >> i got a call from oprah's team and it was still our first year of business. after the show aired, we had 8 million hits on our website. >> reporter: her line began a decade ago with tunics and since expanded to designs like these, seen on the runways of new york.

we have the -- is that the shoe that started it all? >> it was, it was. this was the first classic shoe. >> reporter: you made flats fashionable. and that was important to you. >> it was, for sure. comfort. comfort and style. >> reporter: she's a household name with over 137 free-standing stores. >> here's the watches. >> reporter: beautiful. >> we love that they're swiss made. >> reporter: she can now add author to her resume. her new book released this week. her forward written by voek"vog" anna win tour. >> i wanted to do this for a long time. i started thinking about our blog and to show us how much inspires us. we wanted to bring that into a book format. >> reporter: he company has grown into a multibillion dollar empire. burch isn't just involved by name.

she takes part in every detail of the business. >> the most challenging part is to design beautiful things at our price point. we try to create the most beautiful things that fit incredibly well and keep the price as reasonable as possible. so, that's the challenge. >> reporter: for "nightline," i'm amy robach in new york. >> much deserves success. thanks for watching abc news. tune into "good morning america" tomorrow. as always, we're online at abcnews.com. good night. of course i miss ya, ma. what's wrong with sounding happy? why do you say it like it's a negative thing? ok, ok, i'm not that happy. all right, i'll see ya later, ma. [sadder] i mean, i'll see ya later, ma. [swing music plays]

take it, shamsky. [knock on door] just a minute.