If you take a shot of The Departed and mixed in a dash of Medellin (or how it was meant to be in Entourage) then you get Protege. If you’ve seen Infernal Affairs, the Hong Kong thriller that The Departed was based on then you’ll see many allusions to the plotline. In fact Andy Lau produced and starred in both movies.
Anyways, the story revolves around an undercover cop climbing the ranks of a major heroin cartel. The head of the gang is sick and wants to pass on the mantel to his protege, the cop, and goes on showing him the ropes. The movies not only delves into the intricacies and dangers of the drug trade but draws a clear line on where it stands in mess. Heroin use is fucked up. Check it out. Definitely worth your time.