Martin Vail (Richard Gere) is a Chicago defense attorney who loves the spotlight and does everything he can to get his high-profile clients acquitted on legal technicalities. One day, he sees a news report about the arrest of Aaron Stampler (Edward Norton), a 19-year-old altar boy from Kentucky with a severe stutter, who is accused of brutally murdering the beloved Archbishop Rushman (Stanley Anderson). Vail jumps at the chance to represent the young man, pro bono.
During his meetings at the County jail with Stampler, Vail comes to believe that his client is innocent, much to the chagrin of the prosecutor (and Vail’s former lover), Janet Venable (Laura Linney).
As the trial begins, Vail discovers that powerful civic leaders, including the corrupt state’s attorney John Shaughnessy (John Mahoney), have lost millions of dollars in real estate investments due to a decision by the Archbishop not to develop on certain church lands. The Archbishop received numerous death threats as a result. Following a tip from a former altar boy about a videotape involving Stampler, Vail makes a search of the Archbishop’s apartment and finds a VHS tape of Stampler being forced to have sex with another altar boy and a girl named Linda Forbes. Vail is now in a dilemma: introducing this evidence would make Stampler more sympathetic to the jury; but it would also give him a motive for the murder, which Venable is unable to establish.
When Vail confronts his client and accuses him of having lied, Stampler breaks down crying and suddenly transforms into a new persona: a violent sociopath who calls himself „Roy“ and confesses to the murder of the Archbishop. When this incident is over, Stampler once again becomes passive and shy, and appears to have no recollection of the personality switch – what he calls having „lost time.“ Molly Arrington (Frances McDormand), the psychiatrist examining Stampler, is convinced that he has dissociative identity disorder caused by years of abuse at the hands of his father. Vail does not want to hear this, because he knows that he cannot enter an insanity plea during an ongoing trial. [Wikipedia]