The film is told out of chronological format, the story being told from four different points of view. As such, the following summary only generalizes the actual sequence of events which take place.Ronna's storyIt is Christmas Eve in Los Angeles. Adam (Scott Wolf) and Zack (Jay Mohr), a couple of TV soap opera actors, have been busted for narcotics possession. In a plea deal, they will help Officer Burke (William Fichtner) set up a sting operation for Simon (Desmond Askew), an occasional drug dealer who sells ecstasy from his cash register at a local grocery store. Unbeknownst to them, Simon has taken a vacation to Las Vegas. Filling in at his register is Ronna (Sarah Polley), an 18-year-old runaway and high school dropout who is facing eviction and desperate for the extra paid hours of income. When the actors ask about Simon and where they might buy some ecstasy, Ronna recognizes a lucrative financial opportunity. She offers to "see what she can do" for them, taking down their address. They give her a flier with the details of a rave later that evening.After work, Ronna and co-worker friends Claire (Katie Holmes) and Mannie (Nathan Bexton) debate the underground drug trade "rules," such as circumventing Simon to become competing dealers themselves. Ronna decides this will be a one-time-only deal and proceeds to Simon's drug supplier, Todd (Timothy Olyphant). Todd is suspicious of Ronna's sudden interest in dealing drugs, and that the quantity she has requested is the exact amount that constitutes a drug trafficking felony. Reluctantly, he offers to sell her the drugs at a higher price. Unprepared for the price hike, she offers to leave collateral in exchange for bringing the balance back after the sale is complete, and bullies Claire into being the collateral. Ronna and Mannie then proceed to Adam and Zack's pre-rave party at their apartment. Ronna goes inside to complete the deal, while Mannie stays in the car and downs two of the pills he swiped from the bottle.Inside at the "party", there's only Adam and Zack behaving uncomfortably, along with an older man (Officer Burke, the undercover officer) who seems overly focused on finishing the drug deal. Ronna quickly realizes something is amiss here, so she asks to use the restroom before completing the deal. When Zack turns to show Ronna the way to the bathroom, he whispers "Go!" to her. She goes into the bathroom, flushes the drugs down the toilet, and emerges empty-handed. She tells Burke she wasn't able to obtain the drugs after all, and to defend herself from further scrutiny, notes to Burke that she is underage to be drinking the beer he gave her. Realizing he is now on surveillance giving alcohol to a minor, and without evidence to hold her, Burke lets Ronna go.Ronna, in a state of panic, ponders her situation with Mannie, who is slowly succumbing to the effects of the pills he took. She doesn't have the money to buy Claire's release from Todd, and now she has no drugs to sell. In desperation, she shoplifts a large supply of over-the-counter medication from her own grocery store. Finding pills roughly the same appearance as the ecstasy pills, she refills Todd's bottle and returns to his apartment. She explains to Todd that the deal fell through, gives the "stash" back to him, and frees Claire from collateral duty. Ronna realizes that she's still facing eviction and decides to attend the rave to sell the remaining medication as ecstasy. Her scam works, and she quickly makes more then enough money to cover her rent. Meanwhile, Todd has discovered the fake pills and shows up at the rave to settle the score. He sees Ronna and Mannie from afar and chases them through the dancing crowd. Mannie is too high to run and is slowing them both down. Ronna hides Mannie behind a piece of sheet metal in a back alleyway, tells him to keep quiet until she comes back, and runs off alone.Todd catches up to Ronna in the parking lot. He has a few last words with her about the nature of the illegal drug trade, and takes out a gun intent on killing her. At that very moment, a yellow Mazda Miata swerves around a corner of the parking lot at high speed and squarely hits Ronna, catapulting her onto its roof. It then shoots forwards and stops suddenly, sending her flying into a ditch. The driver, in panic from seeing Todd with a gun, flees the scene. Todd leaves Ronna for dead and flees as well as it begins to rain. Ronna lies motionless in the ditch.Simon's storyEarlier.... After recruiting Ronna to cover his shift at the grocery store, Simon goes off with three of his friends Marcus (Taye Diggs), Tiny (Breckin Meyer), and Singh (James Duval) for some adventures in Las Vegas, footing their hotel bill with the credit card he had borrowed from Todd. Shortly after arriving, Tiny and Singh develop bad cases of diarrhoea from eating some bad seafood at the hotel's buffet restaurant and are stuck in their hotel room while Simon and Marcus hit the casino. Simon quickly loses much of his money and then wanders into a wedding party on the premises. There, he meets two female guests, with whom he eventually smokes pot and has sex (both of them). One of the women accidentally starts a fire in her hotel room, causing Simon to flee naked (clothes in tow) in an elevator.Putting his clothes back on, he meets up with Marcus back in the casino. Marcus's yellow sports coat gets him mistaken for a hotel employee, even earning him a tip when a customer mistakes him for a bathroom attendant. This eventually works to his advantage, though, when another hotel guest assumes Marcus is a parking valet and hands him the keys to his Ferrari. Simon and Marcus jump at this golden opportunity to take the red Ferrari for a spin, winding up at the Crazy Horse strip club. En route, Simon discovers a 9 mm pistol in the glove compartment, which he pockets for himself.At the strip club, Marcus warns Simon not to order "champagne" - strip club code for a private lap dance they cannot afford - however, Simon does precisely that, and he heads to a back room with two dancers and Marcus in tow. Before the lap dance commences, they receive a stern warning from menacing Victor Junior (Jimmy Shubert), one of the bouncers and the son of the club owner, to behave like gentlemen and not touch the dancers "or else." Simon hands the bouncer Todd's credit card and he and Marcus enter the back room; the lap dances have barely begun when Simon loses his self-control and gropes his dancer. Victor Jr. immediately bursts into the room and begins beating him. Marcus tries to defend Simon and is himself attacked by the bouncer. Simon then draws the gun he found and shoots Victor Jr., wounding him in the arm. Simon and Marcus hastily flee the premises and head back to the hotel.Simon and Marcus rush into their room and roust up the sickly Tiny and Singh, telling them they have 30 seconds to get up and out. Before they can flee, the Victors Jr. and Sr. (J.E. Freeman) arrive at their door, so Simon and crew bribe a young boy staying in the next room to open the connecting door for their escape. After a frantic car chase down the Las Vegas Strip, Simon and his three friends manage to elude their pursuers and reach the highway back to Los Angeles and drive away in the light of dawn in Simon's damaged car. They believe they are safe, reasoning that their pursuers would have called the police in Vegas...or so they think. What Simon forgets is that it was Todd's credit card he left back at the strip club.Adam and Zack's storyEarlier... Adam and Zack are actually closeted gay lovers forced to be decoys in a police sting operation, in exchange for having their own drug charges dropped. In the grocery store parking lot, they test out their hidden microphones; inside, they look for Simon, their usual dealer, but find only Ronna. Later, after the sting with Ronna goes bad, Burke handcuffs Zack, then makes a bizarre suggestion: Why don't they spend Christmas Eve at his house and have dinner? Nervous, they reluctantly accept his invitation.It is an odd atmosphere in the house, and Zack and Adam have odd encounters with Burke and his wife Irene (Jane Krakowski). Zack comes out of the bathroom and runs into Burke completely nude; Burke urges him to lie down on his bed and try out some cologne. Adam, meanwhile, meets Irene, who comes on to him and even kisses him full on the lips. Later, when the four sit down to Christmas dinner, Burke explains that he and his wife are the fourth leading sales team in the region for Confederated Products, an Amway-type retail company, and that virtually everything in the house from the food to the cologne is from the company. Burke wants Adam and Zack to sell Confederated products for him. Zack then gets Adam to feign illness to excuse themselves, and they leave the house, both of them uneasy from the evening's events.Adam and Zack engage in small talk and discover that both of them are cheating on each other with the same man, Jimmy, a makeup artist in their television studio. They go to Jimmy's apartment and find out from his sister that he is attending the same rave that they had earlier advertised to Ronna. Adam and Zack show up and get revenge on their mutual two-timing lover by holding Jimmy down and cutting a sizable chunk of his long hair.Satisfied, they leave the party, get into Adam's yellow Miata and barrel into Ronna, sending her flying into the ditch. Then they see a man with a drawn pistol (Todd) and, terrified, flee the scene.They stop at a gas station and try to figure out what to do, debating whether Ronna survived the accident and, if so, whether or not the man with the gun finished her off. Adam goes to the toilet where he realizes that he is still wearing the hidden microphone from earlier that afternoon. Panicked, they throw the devices away and drive back to the spot where they hit Ronna. They find her still lying in the ditch, unconscious but alive, and hoist her on top of a nearby car with the alarm blaring. They watch in satisfaction from afar as other partygoers discover Ronna early the next morning and call an ambulance for her.ConclusionIt is dawn now, and Claire, who does not know what happened to Ronna, leaves the rave and goes to the diner where she usually meets Ronna when they get separated. She encounters Todd; they engage in small talk, then realize they are attracted to each other. They end up kissing and groping in the stairwell of Todd's house, where they are discovered by none other than Victor Jr. and Victor Sr., the Crazy Horse bouncer and owner whom are after Simon and have tracked him through Todd's credit card. Todd explains they have the wrong man; he begins to draw out directions to Simon's place, when Simon himself walks into Todd's apartment ironically, to seek refuge from the bouncers. At first they want to kill him, but Claire points out that she and Todd would be witnesses to the crime. So an "eye for an eye" deal is struck where Victor Jr. gets to shoot Simon in the arm. Just as he is about to get justice, performance anxiety suddenly springs upon Junior and he cannot bring himself to pull the trigger. Claire gets impatient and leaves during his hesitations; as she gets halfway down the hall she hears a gunshot. She flinches and shuts her eyes. Simon calls out: "It's all right... I'm okay!"Meanwhile, Ronna wakes up in the hospital recovered enough to return to work, happy that, despite the night's batterings, she did indeed make enough money to save herself from eviction. She talks with Claire and suddenly realizes to her horror that she never went back for Mannie, who is presumably still hidden where she left him. Ronna and Claire return to the scene and find Mannie still there, shivering and terrified, but otherwise okay. They all get into Ronna's car and drive away, and Mannie wonders aloud what they'll do for New Year's Day just a week away.
Output: Question: who refuses to witness a murder?, Answer: Claire