Ben Affleck plays an autistic savant who’s a whiz at maths and a dab hand at killing people, too.

Affleck’s solitary character is on the high-functioning end of the autistic spectrum and he has found a niche occupation to suit his skills.

A forensic accountant with a rather specialised clientele, he works for drug cartels, arms dealers, money launderers and the Mob. If anyone has been cooking the crooks’ books, he’s the man who will find out.

He moves in dangerous circles, so it’s handy that he doesn’t just crunch numbers. Put by his martinet military dad through a punishing regime of combat training during his childhood, he is a crack shot and lethal unarmed fighter.

But with suspicious US treasury agents JK Simmons and Cynthia Addai-Robinson trying to uncover his identity, he takes a rare legitimate job for a robotics company, only for the gig to turn deadly after Anna Kendrick’s chipper accounts clerk finds a multi-million-dollar hole in the books.

Of course, the far-fetched plot hardly stands up to close scrutiny, but the film’s flaws don’t detract from its incidental pleasures and there’s no doubting that it delivers on the entertaining shoot-’em-up thrill front.