In 1970, Shasta Fay Hepworth (Katherine Waterston), visits the rickety beach house of her ex-boyfriend Larry "Doc" Sportello (Joaquin Phoenix) in Gordita Beach, a fictional town in Los Angeles County. Doc also happens to be a private investigator and hippie/dope head. Shasta tells him about her new lover, Mickey Wolfmann (Eric Roberts), a wealthy real estate developer. She asks Doc to help prevent Mickey’s wife (Serena Scott Thomas) and her lover from having Mickey abducted and committed to an insane asylum.
At his office, Doc meets with Tariq Kahlil (Michael K. Williams), a member of the Black Guerrilla Family. Khalil hires Doc to find Glen Charlock (Christopher Allen Nelson), a member of the Aryan Brotherhood he met in jail, who now owes him money and is one of Wolfmann's bodyguards.
Doc visits Mickey's Channel View Estates project and enters the only business in the developing strip mall, a brothel/massage parlor, where he meets an employee, Jade (Hong Chau). Doc searches the premises for Charlock, but he is knocked on the head with a baseball bat and collapses. He awakens outside, lying next to Charlock's dead body and surrounded by policemen. Doc is brought to the police station and interrogated by Detective Christian F. "Bigfoot" Bjornsen (Josh Brolin) of the LAPD. Here, Doc is helped by his attorney, Sauncho Smilax (Benicio del Toro).
Doc then takes on his third "case" of the film. He is hired by former heroin addict, Hope Harlingen (Jena Malone), who is looking for her missing husband, Coy (Owen Wilson). She was told that Coy was dead; but she believes he is alive because, shortly after his supposed death, there was a large deposit to her bank account. Coy searches for Doc and says he is hiding at a house in Topanga Canyon. In a second meeting, he reveals he is a police informant and fears for his life, only wanting to return to his wife and daughter.
At his office Doc finds a message from Jade who apologizes for setting him up with the police and tells him to "beware of the Golden Fang". He meets her in an alley, where she explains that the Golden Fang is an international drug smuggling operation. Doc talks to Sauncho, who gives him some information on a suspicious boat called the Golden Fang and tells him that, the last time the ship sailed, it was with Shasta on board. Thanks to a postcard from her, Doc finds a large building shaped suspiciously like a golden fang and meets with the dentist Dr. Rudy Blatnoyd (Martin Short).
The day after, Bigfoot calls Doc and tells him that the dentist has just been found dead with a neck injury – fang bites. Bigfoot also decides to help Doc about Coy and tells him to search for Puck Beaverton (Keith Jardine) in Chryskylodon, an insane asylum run by a sort of cult with a connection to the Golden Fang. There, Doc finds Mickey and manages to talk to him. The man tells him he had been feeling guilty for the negativity that his real-estate business has caused and wants to give away all his money. He now appears to be a happy member of the cult.
When Doc returns home to his beach house, he is greeted by Shasta, who has returned and is indifferent to all the trouble her disappearance has caused. She confesses to being on a "three-hour tour" and that she was brought along as inherent vice. She and Doc have sex; and when she tells him "It doesn't mean we're back together" Doc replies, "Of course not!"
Penny provides Doc with confidential files from which he learns that the loan shark Adrian Prussia (Peter McRobbie) is paid by the police department to kill people for them and that one of his victims was Bigfoot's former partner. Prussia is tied to the Golden Fang and Doc learns that Glen Charlock was involved with a deal, which is how he ended up dead. Doc visits Adrian, noticing his obsession with baseball bats, but is abducted and drugged by his partner Puck. He manages to escape, killing both Puck and Adrian. Bigfoot appears and rescues Doc but after driving him home, Doc learns that he has been set up and some smuggled heroin has been planted in his car. He then successfully arranges for the drugs to be returned to the Golden Fang in exchange for Coy's freedom.
Mickey Wolfmann is in the newspaper again, having returned to his previous state as a wealthy, money-driven businessman. One can infer that his trip to Chryskylodon helped him change his mind about giving away all his money, and was set up or encouraged by his wife to maintain her lifestyle.
Fuente:
http://en.wikipedia.org/wiki/Inherent_Vice_%28film%29