Locked In review – lurid Netflix thriller isn’t quite lurid enough

Crashing rain, a remote countryside mansion, illicit sex, a British-accented Famke Janssen holding a shotgun while riding a horse – one might easily assume that lurid Netflix thriller Locked In is a four-wines-in blast. At times it threatens to be, usually when at least two of those aforementioned elements are in play, but it’s all tease and no payoff, the heightened silliness of the first act wearing wafer-thin by the last, charmingly farfetched turning into an annoyingly far reach.

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Written by Rowan Joffe, whose adaptation of SJ Watson’s enjoyably nutty thriller Before I Go to Sleep handled a similar balance far more effectively, Locked In also feels as if it’s based on an airport-bought page-turner. There are flashbacks, a potentially unreliable narrator, shifting perspectives, a hidden diary – the same ingredients that Gillian Flynn turned into magic with Gone Girl – but it all amounts to very little here, cruelly fooling us into the expectation of something far twistier. Janssen plays Katherine, an ex-actor who has been involved in an accident that’s led to locked-in syndrome, a puzzle for an inquisitive nurse, played by Anna Friel, to figure out. Katherine’s adopted daughter Lina (Rose Williams, giving her best Alicia Vikander impression) seems to know more than she’s letting on, but who is the real victim and who is the real villain?

In her feature debut, Lebanese director Nour Wazzi has some fun leaning into the gothic schlock of Joffe’s premise, drenching Katherine’s lavish mansion in darkness and rain, playing into the goofy fairytale setup. Lina’s mother dying young, leaving her to be adopted by Katherine, her richer friend, who locks horns with her stepson over the inheritance from her dead husband; it’s all incredibly silly, but seductively so, for the first half. But playing detective is only fun until the murk clears up and we see where we’re headed – to nowhere all that surprising, a film such as this in need of a wilder, more ground-shifting twist to distinguish itself from the pack. Janssen is also left a little adrift by Joffe, the prospect of her snacking on scenery as a shotgun-wielding ex-TV star never quite paying off in the campy ways we might want and expect. Friel is as excellent as ever, but her underwritten role is so thankless that one wonders if her appearance was some sort of favour to a friend.

Her appearance here is a more compelling mystery than the one at the film’s centre, which even at a relatively brief 96 minutes feels overstretched and underbaked. Aping the format and tease of a novel that you just can’t bear to put down, Locked In is instead a film you wish you would have stopped far earlier.

• Locked In is now available on Netflix