Los Angeles, 1949. Ruthless, Brooklyn-born mob king Mickey Cohen (Sean Penn) runs the show in this town . . . that is, until a crew of LAPD officers led by Sgt. John O'Mara (Josh Brolin) and Jerry Wooters (Ryan Gosling) wage war on his empire. Gangster Squad also stars Nick Nolte, Emma Stone, Anthony Mackie, Giovanni Ribisi, Michael Peña, and Robert Patrick.