Series 2 commissioned after record ratings. New cast includes Meera Syal, Clive Russell, and Richard Ayoade.

Detective Inspectors Major and Carver are the top crime-fighting duo at the Met Police's Special Investigation Unit until Major is gunned down on the job; in an experimental project, Major is brought back from the dead.

In season two of CODE 404, there’s still a few bugs to patch out. Having cracked a high-profile case with his long-suffering partner, the resurrected DI Major has finally reached his potential as the top cop in the SIU. But it came at a price. At last realizing that his best friend had shacked up with his wife Kelly (Anna Maxwell Martin) while he was “away” (and a bit before), their partnership is over, and the pair go their own ways. But when a 20-year-old cold case is reopened, the pair find themselves back together and thrown into the action.