The stool pigeon (2010)

Living in the guilt of sacrificing his informant in a previous operation, Criminal Intelligence Inspector Don Lee is wary when his superior orders him to send another informant to spy on the criminal operations of Barbarian, a vicious gangster plotting a jewelry heist. He seeks ex-convict Ghost, who agrees to work for Don despite vowing to go straight since he's desperately in need of money to repay a debt and save his sister. Ghost's driving skills help him infiltrate Barbarian's gang and earn his trust, but by feeding information to Don and hooking up with Barbarian's girlfriend Dee, Ghost is pushing himself into a tight and deadly corner...