In the irreverent spirit of fun that made The LEGO Movie a worldwide phenomenon, the self-described leading man of that ensemble, LEGO Batman, stars in his own big-screen adventure. But there are big changes brewing in Gotham, and if he wants to save the city from the Joker's hostile takeover, Batman may have to drop the lone vigilante thing, try to work with others, and maybe, just maybe, learn to lighten up.

In South Boston, the state police force are waging a war on Irish-American organized crime. Undercover cop Billy Costigan is assigned to infiltrate the mob syndicate, which is run by gangland chief Frank Costello. Billy quickly gains Costello's confidence. Colin Sullivan is a hardened young criminal who has infiltrated the police department as an informer for the syndicate. Colin is rising to a position of power within the Special Investigation Unit....