Robbie Collin is not impressed with this tepid thriller starring Emma Watson and Ethan HawkeEthan Hawke is one of the most naturally plausible actors working today, but Regression has defeated him. Not even he can sell you on the psychological turmoil of a man who's haunted by a sachet of Cup-a-Soup.This is, believe it or not, one of the less absurd twists of Alejandro Amenábar's thriller in which Hawke plays Bruce Kenner, a Minnesota cop who's investigating a suspected outbreak of devil-worship.From its occult premise to the voguishly dingy 1990s period setting, the film desperately wishes it were True Detective - though its plot feels heavily inspired by the notorious West Memphis Three case of 1993, in which a trio of Arkansas teenagers were wrongly convicted of murdering three young boys in a stomach-churning blood rite.The victim here is still alive, but only just. She's Angela (Emma Watson), a frail teenager whose father John (David Dencik) confesses to having sexually abused her, even though he has no specific memory of the crime.Baffled, Kenner turns to Dr Raines (David Thewlis), an English hypnotherapist with both the appearance and personality of an illegally dumped armchair.The doctor uses regression therapy to draw out the gory particulars. Angela, it transpires, was an unwilling participant in some dread Satanic ceremony - and further details gleaned from her waifish runaway brother (Devon Bostick) and distressed-leather handbag of a grandmother (Dale Dickey) paint a truly Boschian picture of child sacrifice and ritualistic rape in the moonlit backwoods. Kenner is shaken, and suspects he might be the next target. And this is where the Cup-a-Soup comes in. Amenábar is no stranger to psychologically vivid thrillers with ghostly overtones, but Regression feels depressingly like journeyman work. A few flourishes make an impression but they're exclusively visual, and tend to be defanged by the corny sound effects (so much backwards whispering) and snarlingly unsubtle score.Watson should be the film's unnerving heart, but her role is pure cardboard. As for the wisdom of building a did-she-didn't-she guessing game around a vulnerable young woman's rape testimony, the choice feels at best unfortunate. The West Memphis Three case has already been well-served by cinema, in Atom Egoyan's procedural Devil's Knot , the Paradise Lost documentaries and Amy Berg's excellent West of Memphis . Those took a sober tack that was at shivery odds with the lurid material. Regression fails by trying to have it both ways: you can't feel sceptical and scared at the same time.Rating: 2/5 stars- © The Telegraph, London..