Los Angeles, 1949. Ruthless, Brooklyn-born mob king Mickey Cohen (Sean Penn) runs the show in this town, reaping the ill-gotten gains from the drugs, the guns, the prostitutes and — if he has his way — every wire bet placed west of Chicago. And he does it all with the protection of not only his own paid goons, but also the police and the politicians who are under his control. It’s enough to intimidate even the bravest, street-hardened cop… except, perhaps, for the small, secret crew of LAPD outsiders led by Sgt. John O’Mara (Josh Brolin) and Jerry Wooters (Ryan Gosling), who come together to try to tear Cohen’s world apart.
It's 1949 Los Angeles, the city is run by gangsters and a malicious mobster, Mickey Cohen. Determined to end the corruption, John O'Mara assembles a team of cops, ready to take down the ruthless leader and restore peace to the city.