Scorsese is very much in his element with this stylish crime drama about corruption and collaboration between the Boston police department and the criminal underworld. Matt Damon plays a superstar young cop who rockets to the top of the force, but it turns out he's feeding tips to crime boss Jack Nicholson, in order to line his own pockets and keep the gangsters one step ahead of the law. Meanwhile, a young man (Leonardo DiCaprio) with ambitions of joining the force goes undercover for the department in order to prove himself and to infiltrate Nicholson's gang, but his life is put in serious jeopardy once it's revealed there's a rat among the gang, and his superior officer is suspiciously killed when he begins to suspect that someone on the police force is leaking information.
This is one of Scorsese's best films in years, with a solid, unpredictable script and a fine cast (which also includes Mark Wahlberg, Martin Sheen and Alec Baldwin) making the most of their roles. There are echoes of GOODFELLAS and CASINO in its depiction of the criminal underworld, but Scorsese takes a fresh approach by focusing on corruption within the police force and contrasting the character dynamics between a good cop and a bad cop. As a result, it doesn't feel like a re-tread of material we've seen before, instead making this an interesting departure for the director that ranks among his best work.