The film's narrative is driven by the investigation of a series of murders that are inspired by the seven deadly sins: gluttony, greed, sloth, pride, lust, envy, and wrath. The killer, who calls himself John Doe (played by Kevin Spacey), is a meticulous and calculating individual who uses the Bible as a reference point for his crimes. As the story unfolds, detectives William Somerset (Morgan Freeman) and David Mills (Brad Pitt) find themselves entangled in a cat-and-mouse game with John Doe, who seems to always be one step ahead.