Pity Franck Adrien (Albert Dupontel).

A bank robber in Eric Valette’s sharp if dramatically underwhelming French thriller “The Prey,” Adrien is serving hard time and routinely brutalized by fellow prisoners who want to know where he hid his loot.

Prison guards and the warden are conspiring against him, and he’s got a desperate wife (Caterina Murino) with no money to pay for their young daughter’s speech therapy.

But Adrien’s got an even bigger problem he doesn’t recognize until it’s too late: His seemingly mild-mannered cellmate, Maurel (Stéphane Debac), soon to be released, is secretly a serial rapist and killer planning to target Adrien’s family and steal his money.

What follows is an extended, entertaining rush of sometimes breathtaking action as Dupontel’s laconic antihero attempts to save those he loves. Adrien breaks out of confinement and goes to extraordinary lengths to stay a step ahead of the police. “The Prey’s” most exciting moment finds the star visibly leaping onto a moving train, then creatively making it stop in its tracks.

Valette reinforces how high the stakes are for Adrien to catch his foe. That urgency grows as Maurel expertly creates a trail of false evidence implicating Adrien in the former’s many crimes.

Less persuasive is the way “The Prey’s” story becomes jammed by a host of minor characters and their distracting agendas.

Tom Keogh: tomwkeogh@yahoo.com