Six professional gangsters are hired by Joe Cabot and his son Eddie for a job. They are strangers to each other and remain anonymous, hidden under colour pseudonyms. They meticulously plan a jellewry heist, but the police unexpectedly turn up at the crucial moment, with the robbery becoming a massacre. Everything points to a mole in the group, and the survivors must go head-to-head to try and find out who has led them to this extreme situation.