The first trailer has arrived for director Ruben Fleischer's crime noir thriller The Gangster Squad, which recounts the LAPD's efforts to take down Brooklyn-born mob king Mickey Cohen and restore their city's justice. Watch this all-star cast, which includes Sean Penn, Ryan Gosling, Giovanni Ribisi, Michael Peña, Anthony Mackie, Emma Stone, Robert Patrick, and Nick Nolte as they all square off in their efforts at changing Hollywood's crime scene forever.