This overcranked paedophile/child abduction thriller (a Nordic-influenced Belgian/Dutch production from British author Mo Hayder’s bestseller) is as well made as it is occasionally unwatchable. Geert Van Rampelberg is convincingly rattled as Nick Cafmeyer, a detective whose brother was snatched as a child, and whose spectre he now chases through child-abuse cases. Investigating a horrific crime bound up with local tales of “the troll”, Cafmeyer uncovers a web of rape and torture, the details of which become more grotesquely baroque with each foul revelation. His superiors doubt his sanity but oddly we do not; Denis Villeneuve’s Prisoners did a much better job of wrong-footing our vigilante instincts, even as it similarly descended into absurdity. Horribly convincing performances add exploitative heft, while Johan Van Essche’s production design makes the Boschian hell seem all too real.