The Departed Ending Explained

The Departed wraps up in a whirlwind of betrayal and death that leaves no one standing tall. Directed by Martin Scorsese, this crime thriller follows two moles: Billy Costigan, an undercover cop infiltrating gangster Frank Costello’s crew, and Colin Sullivan, a mob plant rising in the Boston police force.https://en.wikipedia.org/wiki/The_Departed

As the story races to its close, Costigan watches Costello hand Sullivan an envelope packed with details on his own crew. Sullivan spots the tail, stabs an innocent man by mistake, and bolts.https://en.wikipedia.org/wiki/The_Departed He tricks the police into tailing Captain Queenan, Costigan’s handler. Costello’s thugs show up, Queenan gets the mole out safely, but they hurl him off the roof to his death.

In the chaos of a shootout, one of Costello’s men, Timothy Delahunt, takes a fatal hit and whispers to Costigan that he knows he’s the rat before dying.https://en.wikipedia.org/wiki/The_Departed Queenan’s death shakes everything up. Sergeant Dignam clashes with Sullivan and gets suspended. Sullivan digs into Queenan’s files and learns Costello has been snitching to the FBI all along.https://en.wikipedia.org/wiki/The_Departed https://www.youtube.com/watch?v=YErszq4QGuA

A news report calls Delahunt a cop undercover, but Costello smells a cover story to hide the real mole. Sullivan calls in state police to track Costello, sparking a bloody gunfight that wipes out most of the gang.https://en.wikipedia.org/wiki/The_Departed Sullivan faces off with the injured Costello, who confesses to being an informant. They shoot it out, and Sullivan finishes him off.https://en.wikipedia.org/wiki/The_Departed https://www.youtube.com/watch?v=YErszq4QGuA

With his mission done, Costigan meets Sullivan to hand over evidence, but spots that same envelope on the desk. It clicks: Sullivan is Costello’s mole inside the cops.https://en.wikipedia.org/wiki/The_Departed Costigan runs for it. Sullivan catches on, wipes Costigan’s records from the system, and pushes for a medal in his “honor.”

At Costigan’s funeral, his shrink and Sullivan’s girlfriend, Madolyn, drops a bombshell: Costigan left her an envelope with a recording of Sullivan’s dirty talks with Costello.https://en.wikipedia.org/wiki/The_Departed https://the-departed.fandom.com/wiki/Billy_Costigan She’s pregnant and walks out on Sullivan. He gets home, and there stands Dignam, who pumps a bullet into him without a word and leaves.https://en.wikipedia.org/wiki/The_Departed https://nofilmschool.com/movies-where-everyone-loses

This ending flips loyalties on their head. Queenan’s death leaves Costigan isolated, and the reveal that Costello ratted to the FBI crumbles the whole power structure both men fought over.https://www.youtube.com/watch?v=YErszq4QGuA Survival kicks in over justice. Sullivan climbs as a hero after killing his boss, but Costigan’s evidence seals his doom through Madolyn and Dignam.https://the-departed.fandom.com/wiki/Billy_Costigan Everyone connected to the mess ends up dead or broken, showing how deep the rot runs in this world of rats and cops.

Sources
https://en.wikipedia.org/wiki/The_Departed
https://www.youtube.com/watch?v=YErszq4QGuA
https://www.independent.co.uk/arts-entertainment/films/features/movie-twists-best-films-all-time-b2887657.html
https://nofilmschool.com/movies-where-everyone-loses
https://the-departed.fandom.com/wiki/Frank_Costello