At 10 years of age, a child the papers called "Boy A" was thrown into juvenile prison for murdering a classmate. Released at age 24, Boy A takes a new name and a new identity, and tries to integrate himself into a society he now finds unfamiliar. He's had no practice at hanging out with the boys at clubs or asking girls out on dates, and when one of his co-workers drops a reference to The Office, the joke sails over his head. As played by Andrew Garfield, Boy A is a gentlemanly sort—albeit in a forced, petrified way—and whatever bad deeds he's done in the past, he's ready to be shut of them. If only the rest of the world would let him.

John Crowley's Boy A—adapted by screenwriter Mark O'Rowe from John Trigell's novel—contemplates questions of sin and redemption, and whether a person can start fresh after spending more than half of his life locked away. Much about the story is overheated—including a wasted detour to examine the relationship between Garfield's caseworker (Peter Mullan) and his troubled teenage son—and its climax hinges implausibly on the uniformly hostile reaction when people learn what Garfield did. But plausibility isn't really Boy A's alpha and omega. The reasons behind Garfield's disconnection from the world matter much less than how he reacts going forward.

Boy A is at its best when Crowley and company show the adult Garfield as a product of social engineering—the scrubbed-clean "new man"—unsure how to behave if, say, his new friends drop an Ecstasy tablet in his mouth, or involve him in a fight. In his mind, Garfield is still obsessively reliving the events that led to his incarceration at 10, and at 24, he's terrified of making the same missteps. No matter how straight he acts, though, he can only hide his secret for so long. For all Crowley's reliance on quiet naturalism, Boy A ultimately steals a page from film noir, showing how guilt and constant hounding can turn any ex-con into the desperate animal everyone presumes him to be.