Black Mass is the true story of James "Whitey" Bulger (Johnny Depp), one of the most notorious gangsters in US history. His brother, Billy (Benedict Cumberbatch), is a senator, and the two of them grew up with a kid named John Connolly (Joel Edgerton), who later in life went on to become an FBI agent. Not wanting to arrest the guy he grew up with, John comes up with a plan for Bulger to become an informant for the FBI, helping John to take down bigger criminals, pushing Bulger higher into power. But the FBI suspect that something's up and start investigating, forcing John to bend the law to protect Bulger, who in turn is protecting him.
However, Depp isn't the only actor in this movie that gets his chance to shine. Black Mass features the likes of Joel Edgerton, fresh off his excellent flick 'The Gift' earlier this year and he's better than ever, Benedict Cumberbatch, Kevin Bacon, Corey Stoll, Dakota Johnson, who proves that she can actually act despite starring in 50 Shades of Grey, Jesse Plemons and Peter Sarsgaard. Despite a few dodgy Boston accents, they're all beyond brilliant, yet Depp still manages to out-act them all, so that's saying something about his portrayal of this despicable, yet intriguing character.
As we further through Bulger's mayhem, something becomes really apparent. This film isn't going anywhere. It's a series of crimes committed by Bulger that all relate to the FBI, and while each of them are entertaining in their own right, the film doesn't flow smoothly. It's repetitive and stretched out, a few of the murder scenes completely unnecessary to the plot at hand, one involving a prostitute in particular. It takes away from the suspense of everything, with the exception of a scene between Depp and Edgerton's character's wife, played by Julianne Nicholson. It's an uncomfortable encounter and it's gripping to watch.
To sum up, Black Mass is led by some absolutely terrific performances, including a haunting Johnny Depp. Unfortunately, the film doesn't live up to its countless fantastic performances, resulting in a gangster movie that's simply good, but not great.