In South Boston, the state police power is taking up arms against Irish-American composed wrongdoing. Youthful covert cop Billy Costigan is doled out to invade the swarm syndicate keep running by gangland boss Frank Costello. While Billy rapidly picks up Costello’s certainty, Colin Sullivan, a solidified youthful criminal who has invaded the state police as a source for the syndicate is ascending to a position of force in the Special Investigation Unit. Every man turns out to be profoundly devoured by their twofold lives, gathering data about the arrangements and counter-arranges of the operations they have infiltrated. In any case, when it turns out to be clear to both the horde and the police that there is a mole in their middle, Billy and Colin are all of a sudden in risk of being gotten and presented to the adversary – and each must race to reveal the character of the other man so as to spare themselves. Yet, is either ready to turn on their companions and confidants they’ve made amid their long stretches covert?