Martin Scorsese finally netted a directorial Oscar for this remake of the Infernal Affairs series of Hong Kong films. It follows the undercover exploits of a Boston cop digging himself into a group of gangsters run by Jack Nicholson’s underworld boss Frank Costello. Meanwhile, Costello has a rat in the police force in the form of Matt Damon. The all star cast sometimes seem to be drowning in ridiculous Boston accents, but Scorsese pulls out all the stops in keeping things tight and –as things come to a head – extremely suspenseful. Mark Wahlberg gives what may be his very best performances, and Scorsese , as always, makes some great choices for accompanying music.