This highly enjoyable action-adventure, set in 117 A.D., tracks a small cohort of Roman soldiers who are trapped far north of their empire’s boundary. A triple whammy of abrupt plot twists (I’ll let the movie itself spring them) has these guys being run ragged by a vengeful posse of blue-painted Picts—primordial Brits with Scottish accents and Viking faces. Up to now, writer-director Neil Marshall has specialized in horror movies (Dog Soldiers, The Descent), but here, he imagines and communicates a remote world with terrific energy and a passion for detail. Michael Fassbender—the film critic turned spy in Inglourious Basterds—gives a magnetic lead performance as Quintus, the most stubborn and resourceful of the Roman band. He’s backed by a strong ensemble of macho charmers with chiseled faces (Dominic West, Liam Cunningham), as well as Olga Kurylenko as a mute Pict and Imogen Poots as the Druidic lass who lives as an outcast in the forest. Marshall’s excellent direction only becomes rushed when the Picts approach Poots’s hut to search for the Romans. Their supposed fear of this beauty’s reputation for witchcraft is alluded to in the dialogue, but it isn’t persuasively conveyed, so you’re obliged to wonder why these otherwise relentless brutes don’t just go busting in. In the end, though, this matters little. Centurion may bring to mind such recent armored entertainments as Pathfinder and the Bruckheimer King Arthur, but (and this is no small compliment) its craftsmanship and freedom from pretension suit it more to comparisons with Anthony Mann’s two classic pursuit-Westerns, The Naked Spur and Man of the West.