Black Mass

Johnny Depp gives a riveting performance as Southie gangster Whitey Bulger

Credit: Warner Bros. Pictures/courtesy Everett Collection

Ice-cold. Dead eyes. Demonic laugh. His face a mask you can't read until he's up in yours. Then run. That's Johnny Depp giving everything he's got in a riveting, rattlesnake performance as South Boston gangster James "Whitey" Bulger in Black Mass. The FBI finally grabbed this Osama bin Laden of gangsters in 2011. The Irish mobster had been hiding in plain sight since 1994. Now 86, Bulger molders in prison, found guilty of 11 of the 19 murders with which he'd been charged.

Jack Nicholson did a fictional take on Bulger in 2006's Oscar-winning The Departed (while a fugitive, Bulger reportedly sneaked in to see the film). Black Mass, smartly directed by Scott Cooper (Crazy Heart), casts a wide if hardly deep net, since the tentacles of Bulger's tale could fill a mini-series or five. The script, by Mark Mallouk and Jez Butterworth, is based on the 2000 book Black Mass: The True Story of an Unholy Alliance Between the FBI and the Irish Mob, by Dick Lehr and Gerard O'Neill. And an unholy alliance it truly was.

Bulger had known FBI agent John Connolly (Joel Edgerton) from the Boston hood. It's Connolly who persuades his fellow Southie to turn FBI informant in return for help in crushing the Italian Mob. Bulger got the best of that deal, leaving the FBI boss (Kevin Bacon) fuming. Edgerton excels at detailing the dread eating at Connolly; the dread also infects his ethical wife, Marianne (a superb Julianne Nicholson), whose quiet scene with Depp instills more terror than a hail of bullets.

But you get the bullets, too, and the gore, especially when Bulger lieutenant Stephen Flemmi, expertly slimed by Rory Cochrane, is on the scene. And duck when Bulger turns his gun on informant Brian Halloran, played with bug-fuck lunacy by Peter Sarsgaard.

Is there any sympathy for the devil that is Whitey? The death of his only son, at age six, clearly rocks him, as it does the boy's mother (a touching Dakota Johnson). But the key path into Bulger is his good brother, William "Billy" Bulger, former Massachusetts Senate president. Billy remains shrouded in mystery. Luckily, Brit acting icon Benedict Cumberbatch doesn't need dialogue to make his character understood. Cumberbatch reveals Billy's loyalty in the space between words. Frustrating? At times, yes. But you forgive the zigs, zags, evasions and subplots for the hardcore power of Depp's performance and the film's portrait of moral rot on both sides of the law. If there's such a thing as a wild ride into the heart of darkness, this is it.