The story set in Boston revolves around a gangster (Damon) who infiltrates the police department and a cop (DiCaprio) who infiltrates the gangs. The two find out that a mole is in each organization and race to find each other's identity.
The remake of the 2002 Hong Kong hit film revolves around a rivalry between the Boston police force and an Irish-American gang. A gangster is chosen to infiltrate the police force while a young police officer is chosen to infiltrate the gang. When their paths cross what will be the result?