The Big Bang
Detectives Poley (William Fichtner), Frizer (Thomas Kretschmann), and Skeres (Delroy Lindo) are interrogating Ned Cruz (Antonio Banderas), a Los Angeles private investigator, who tells them that five years earlier, Russian mobster Skinny Faddeev gave $30 million in blood diamonds as an advance to Anton (Robert Maillet), a boxer, to intentionally lose a fight against his nephew. However, during the fight, Anton unintentionally killed the nephew. When Skinny was found dead, Anton was sentenced to life in prison. While Anton was in prison, he received over 200 letters from a woman named Lexie Persimmon.
Anton gives Ned the job of finding Lexie. Ned is skeptical about his job, since he doesn't have a photo of Lexie. As he starts investigating the various clues, people start dying mysteriously. Ned also notices that a black Lincoln is following him, which he assumes is the Russian Mafia. He finds a clue that leads him to believe that Lexie might be in San Celeritas, New Mexico.
Ned then meets a waitress named Fay Neman (Autumn Reeser)—a particle physics buff—who helps him. Ned meets Simon (Sam Elliott), his wife Julie (Sienna Guillory), and Niels Geck (Jimmi Simpson), a physicist who is conducting an experiment for Simon. Simon is interested only in finding the "God particle" and feels indifferent when Julie tries to warm up to Ned. Ned suspects that Julie might really be Lexie and decides to tell her what is happening. Meanwhile, Anton tracks down Ned to Simon's bungalow. Ned confronts Julie with his suspicions about Lexie's true identity, but Julie has no idea what he is talking about. Ned and Julie hear gunshots, causing Ned to suspect that Anton is at the house.
Realizing that he and Anton have both mistaken Julie for Lexie, Ned tries to save her. When the duo head toward the basement, Ned is astonished to find Niels dressed like a woman, and in a blonde wig. A box containing cosmetics has the phrase "Lex Parsimoniae"—a Latin phrase meaning "When all things are equal, the simplest solution is the best"—printed on it. Ned realizes that Niels had written the letters to Anton, who becomes angered when Niels tries to convince Anton to accept him. In a shootout, Ned is injured and passes out.
The story cuts back to the present day, where it is revealed that Niels and Anton killed each other while the detectives, who had followed Ned to Simon's house, held Ned and Julie hostage. Ned accuses the trio of following him and killing the people he met, also stating that Skinny was killed for diamonds, which his killer never recovered. Ned proves that Frizer killed all the people who could have known about the diamonds. Frizer admits his crimes, for which the other detectives scold him. Ned looks at a glass tank containing a gecko and realizes something; he tells the villains that he knows where Niels stored the diamonds.
The detectives take Ned and Julie to the spot where he had confronted Julie after she had shown him a hidden shoe box. While Julie and Ned are in the car, Skeres and Frizer go to get the shoe box. Meanwhile, Poley spots Julie and Ned signaling each other. He attacks them, but they overpower him and manage to drive the car towards Skeres and Frizer. Skeres and Frizer are disappointed when they discover the diamonds are not in the box. When they see the car coming towards them, they realize what is happening and start shooting. Ned shoots them both dead. Meanwhile, Simon the physicist's experiment destroys his lab and creates a giant crevasse. Ned and Julie speed away in the car, and later pick up Fay.
neo noir, flashback