Currently you are able to watch "The Departed" streaming on Viaplay. It is also possible to buy "The Departed" on Apple TV, Google Play Movies, Rakuten TV, Blockbuster, SF Anytime as download or rent it on Rakuten TV, Apple TV, Google Play Movies, Blockbuster, SF Anytime online.
To take down South Boston's Irish Mafia, the police send in one of their own to infiltrate the underworld, not realizing the syndicate has done likewise. While an undercover cop curries favor with the mob kingpin, a career criminal rises through the police ranks. But both sides soon discover there's a mole among them.