The story is narrated in first person by Porter Wren (Adrien Brody), a columnist and crime reporter for a New York City newspaper with a reputation as a good listener. One night, he attends an after-work party hosted by publishing magnate Hobbs (Steven Berkoff), who has just purchased the newspaper. He is approached by socialite Caroline Crowley (Yvonne Strahovski), whom Porter recognizes from headlines regarding the death of her husband, Simon (Campbell Scott). Simon was a successful movie producer obsessed with capturing authentic life, often disappearing at night to film random things. His body was discovered in the rubble of a demolished building (with little pieces of jade found next to his body). No one could figure out how the body got there, as the site was fenced off and locked up.Caroline invites Porter to her apartment where she shows him confidential police reports related to Simon's still-unsolved death. She asks Porter to investigate and, over a series of meetings, gradually seduces him. Porter, whose relationship with his wife Lisa (Jennifer Beals) and children has become stale, soon gives in. Caroline reveals how she met Simon at a bar, and he proposed to her after a few hours of talking. Caroline had no money or prospects in NYC and said yes. Caroline wants Porter to help find how and why Simon died, as he is the guy that people talk to and tell him all sorts of things. It's been 17 months since Simon died. It is not clear is Simon was in the building before it was demolished.Going through Simon's belongings, Porter forms an image of him as an eccentric and controlling man. He filmed his own life almost obsessively, sometimes with hidden cameras, and subjected Caroline to cruel pranks and mind games for the sake of capturing authentic reactions. She has a vault filled with thousands of memory cards containing footage of these incidents. None of it, however, gives Porter any insights into his death.Hobbs learns of Porter's affair with Caroline and forces him into an investigation on Hobbs' behalf by making threats against Porter's family (He threatens to fire Porter and initiate a medical malpractice suit against his wife, who is a doctor). Hobbs is looking for a particular memory card he believes Caroline is using to blackmail him. When Porter questions her, Caroline admits she is also looking for the memory card.Simon, after beating her in a drinking game, dared her to have sex with a stranger and record the encounter with a hidden camera. She randomly crossed paths with Hobbs and decided to sleep with him. When Simon watched the video, something about it infuriated him and he hid the memory card; after his death, Hobbs began threatening her. Porter, forcing Caroline to admit she only seduced him to enlist his help, leaves in disgust. Outside his house, he is accosted by thugs working for Hobbs, who beat him up and promise to do worse until he finds the video.Porter goes to see Simon's father, who is in a nursing home, but he is unresponsive. Porter discovers a video camera in a bedside table, but the memory card in it only has footage of Simon visiting his father. Meanwhile, Hobbs' men force their way into Porter's house and accidentally shoot and wound his son, causing a distraught Lisa to take the children and walk out on Porter. After attacking Hobbs' lawyer in revenge, Porter watches the nursing home video again and realizes Simon's father had regular visits from a lady named Mrs. Segal (Linda Lavin). He breaks into her house and finds financial records indicating that she has been billing Simon's estate for the visits to Simon's father but also for unknown services at $5000 per month.Before he can find the memory card, Mrs. Segal returns to find him there. After explaining himself, he learns that she is a friend of Simon's family, who became a surrogate mother to Simon after his own mother passed away when he was a child. Wanting to repay her kindness, he arranged a monthly allowance for her once he became rich. Mrs. Segal felt obligated to earn the money and became a caretaker of sorts to Simon's father. Questioned by Porter about the charges to the estate, Mrs. Segal reveals she was asked by Simon before his death to send copies of a memory card to Hobbs every month. Never having seen what is on it, she gives her last remaining copy of the card to Porter. Watching it, he sees that Hobbs and Caroline had a long and intensely personal conversation (where Hobbs revealed that his penis was butchered by random thugs in France, when he was 20 years old. Caroline also whispered a secret about her stepfather to Hobbs, but this was not audible in the video) before they had sex.Porter returns the video to Hobbs, ending the threat against him and his family. In a show of good faith, Hobbs gives him a key his men found when searching Caroline's apartment for the video. Porter figures out the key is for the basement lock of the building where Simon was found. He goes there and discovers another hidden camera. The memory card in this one reveal Simon took Caroline to the building the night he died. Having watched the sex tape, he demands to know a dark secret about her stepfather that she revealed to Hobbs. Caroline refuses to divulge the story to Simon. So, Simon puts a padlock around Caroline's ankle and swallows the key. Caroline kills Simon during the interrogation and since the building is to be demolished the following morning, Caroline has no choice but to cut into Simon's stomach to retrieve the key and get out of the building.The next morning, Porter meets Caroline and reveals the recording. He gives her a copy, with the original as insurance against her contacting his family (something she had previously done for her own enjoyment). She in turn reveals the secret she told to Hobbs but kept from Simon. Basically, as a little girl, Caroline wanted a horse, and her stepfather never gave her one. She begged and begged and then her stepfather starting sexually abusing her with the promise to get her a horse by her next birthday. On the birthday, the stepfather drives Caroline to a farm to present a horse to her, only to shoot him right in front of her eyes. Porter wishes her well and leaves.In voiceover, Porter expresses guilt for all that happened, including his divorce, while admitting that the experience has both corrupted him and revealed an inner darkness that was always there. In the final scene, Porter drives by the house of a now-remarried Caroline and they look at each other one last time.