The smartest thing Verity does is cast against type. Hathaway, an actress whose warmth has always been her signature, weaponizes that familiarity here. Even when she's motionless in a hospital bed, her presence looms over every frame like a storm front. When the film finally lets her off the leash - and it does, in a handful of flashbacks and one genuinely chilling late-stage sequence - the effect is nuclear. This is not the lovable star of The Princess Diaries; this is something colder, calculating, and unnervingly still.
Johnson, meanwhile, gives Lowen a jittery, wounded quality that grounds the film's more outlandish turns. She's the audience surrogate, and she sells every escalating red flag with a believable mix of dread and morbid curiosity. Hartnett continues his impressive career renaissance, playing Jeremy as a man whose charm might be genuine or might be a mask, and the ambiguity is the point. The supporting cast - including Brady Wagner as the Crawfords' young son Crew and Ismael Cruz Cordova as a sharp-eyed local - rounds out the world without stealing focus.
Showalter's direction is more workmanlike than inspired, but he knows how to frame a creepy hallway and when to let silence do the heavy lifting. The screenplay's biggest weakness is its reliance on a few too many convenient discoveries - Lowen stumbles onto damning evidence with a frequency that strains credulity. And the third act, while satisfying, tips into melodrama that undercuts some of the film's more insidious tension. Still, the pacing is relentless, and the central mystery holds together better than most entries in this crowded subgenre. Fans of the novel will find the major beats intact; newcomers will likely walk out debating that final twist.
What's most surprising is how mean the movie allows itself to be. There's no last-minute softening, no attempt to make anyone fully sympathetic. Verity understands that the best thrillers are about people doing terrible things for reasons they've convinced themselves are noble, and it commits to that ugliness without flinching.