JOHN Connolly and James "Whitey" Bulger grew up together on the streets of South Boston, USA.
Decades later, in the late 1970s, they would meet again.
By then, Connolly was a major figure in the FBI's Boston office and Bulger had become godfather of the Irish mob.
What happened between them - a dirty deal to trade secrets and take down Boston's Italian Mafia in the process - would spiral out of control, leading to murders, drug dealing, racketeering indictments and, ultimately, to Bulger making the FBI's 10 most wanted list.
When he was arrested in 2011, Bulger had been on the FBI's 10 most wanted fugitives list for 12 years.
The $2 million reward the FBI offered for information leading to his capture was larger than that for any other fugitive on the list except Osama bin Laden.
Black Mass is the cinema version of the New York Times best-seller Black Mass: The True Story of an Unholy Alliance Between the FBI and the Irish Mob, written by Dick Lehr and Gerard O'Neill.
This film is Johnny Depp's return to dramatic roles, after many successful years of cementing his Hollywood blockbuster credentials with caricatures of comedic roles (alas Jack Sparrow).
Depp's impersonation of Bulger is beyond convincing, but will it impress enough to give him an Oscar? It should at least earn him a nomination.
Joel Edgerton is the big surprise in this role, offering a character that is convincing and well-executed.
The weakest point of this film is its direction, which feels feeble at times and only average at best.
Is there too much violence in this film? After too much speculation, and for a film about organised crime, there is no ongoing violence although the truly violent scenes can be really disturbing.
As it is based on a true story, this film has treated its subjects with fairness, if not respect.
I would love a sequel - fictional or not - about Bulger's years running from the law.
Those angry, piercing blue eyes make for great cinema.
Stars: Johnny Depp, Benedict Cumberbatch, Dakota Johnson
Director: Scott Cooper
Reviewer: Javier Encalada