Patrick Bateman is the main protagonist of the film American Psycho. He lives in 1980's Manhattan and works on Wall Street. The very image of a yuppie, he is obsessed with his health, cleanliness, appearance, money, and music collection. He has a darker side, however, and feels compelled to commit murder, moonlighting as a serial killer.
Many of Bateman's murder victims are homeless people, one of whom he rants at for not having a job before hand. He lures Paul Owen, who works at another firm, to his apartment, where Bateman axes him to death because he got an account that Bateman wanted. He then disposes of the body, breaks into Paul Owen's apartment, packs his clothes into a suitcase, and rerecords the answering machine's greeting to say that Owen has left for London. Later, he picks up two prostitutes, giving them his name as Paul Owen, brings them to his apartment, and has sex with both of them, while videotaping it. Just as they are about to leave, he opens a drawer full of scary looking devices, takes ot what used to be a coathanger, and growls "we're not finished yet!" The prostitutes are bruised and bleeding by the time he lets them leave. Bateman takes his secretary home one night, and tries to kill her from behind with a nailgun, but fails because the phone rings at the wrong time and he momentarily regains his humanity. A few days later, he picks up one of the same two prostitutes, phones up a lady friend of his, and brings them to Paul Owen's apartment. He drugs the wine, and gets them to make out. He then cuts up his friend with a chainsaw and sticks the body parts in the closet. He ends up chasing the prostitute out into the hallway, and she makes it down the stairs ahead of him. Bateman drops the chainsaw over the edge, which hits and kills the prostitute just before she gets away.
Several nights later, Bateman is at the ATM when it flashes the message "kill a stray cat." He picks up a stray cat and pulls out his gun, but an old woman sees him and cries out. Bateman drops the cat and shoots down the old woman. Two police cars roll in with sirens blaring, and Bateman unloads his gun at them, causing the cars to explode. Bateman flees to his office, where he calls up his lawyer and leaves a message confessing everything.
Bateman awakes the next morning, and is surprised the cops aren't looking for him. He goes to Paul Owen's apartment, only to find that it is completely empty and up for sale. He goes to work, and then goes for a drink with some coworkers. He meets his lawyer there, who compliments Bateman on his great "gag." When Bateman insists that he killed Paul Owen, his lawyer balks, saying that Owen called him from London the night before. Bateman has an epiphany right then and there: that the world has become overly superficial, people are only priorities in what benefits them. So they are in denial or naive of his actions. No one knows each others' name so when Bateman kills someone, everyone thinks it is someone else; as he confesses to his lawyer, his lawyer says he talked to him the other day; either Bateman doesn't know who he killed or the lawyer didn't know who he talked to. Also like the lady selling the apartment, no one is going to pay full price for an apartment where murders have taken place, so she had to rid the place of its bodies and place flowers to hide the scent of decay.