Plot Summary

Rookie police officer Billy Costigan (Leonardo DiCaprio), who grew up in South Boston, is the perfect candidate to infiltrate the Irish mob led by crime boss Frank Costello (Jack Nicholson). Embedded deep within Costello’s criminal organization as an undercover informant, Billy’s mission is to earn the gangster’s trust while secretly feeding intelligence back to his superiors, including (Mark Wahlberg) and (Martin Sheen), to help bring Costello down.

At the same time, state police officer Colin Sullivan (Matt Damon) has risen through the ranks with ease, earning the complete confidence of his colleagues. What no one suspects is that Sullivan is himself a mole—secretly working for Costello from within the police force. As both men operate double lives on opposite sides of the law, the risk of exposure grows, pushing each toward paranoia and fatal consequences.

Praised by critics for its tension and performances, The Departed centers on the inevitable collision between criminals living behind carefully constructed identities. Directed by Martin Scorsese, the film delivers a gripping crime drama that explores loyalty, betrayal, and the destructive psychological toll of a life built on deception, brought to life by a powerhouse ensemble cast.