Warner Bros. has released the first trailer for Gangster Squad, the 1940s-based L.A. mob film starring Sean Penn, Ryan Gosling, Emma Stone, Josh Brolin, and many more.

Here’s a synopsis:

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.

Take a look at the trailer below:

The film is directed by Ruben Fleischer (Zombieland), and in addition to the aforementioned cast, stars Giovanni Ribisi (Avatar), Mireille Enos (“The Killing”), Nick Nolte (Warrior), Michael Peña (Crash), Anthony Mackie (The Hurt Locker), Robert Patrick (Terminator 2), and Josh Pence (The Social Network). What do you think at this first look?