Francois Ozon's tricky thriller relies on its smoothly unrippled surface, leisurely pacing and slightly awkward performances to create a false sense of security that sets up viewers for a shock when it takes an abrupt turn into Patricia Highsmith territory. Successful, middle-aged English novelist Sarah Morton (Charlotte Rampling), who writes popular mysteries featuring the continuing character Inspector Dorwell, is in a rut. She's crippled by writer's block and suspicious that her longtime publisher, John Bosload (Charles Dance), is more interested in newer writers than old stalwarts like herself — "old" being the word that stings. John suggests that Sarah borrow his summer house in the South of France; she accepts, thinking a change of scenery could be inspiring and hoping John might join her for an occasional weekend — the extent of their personal involvement is tantalizingly unclear. Sarah starts writing "Dorwell on Vacation" and eases into the gentle rhythms of nearby Luberon, where she shops in the local markets and eats lunch at the town's small cafe, flirting diffidently with waiter Franck (Jean-Marie Lamour). Then Hurricane Julie (Ludivine Sagner) blows in. Julie is John's neglected teenage daughter; she despises her father for abandoning Julie and her mother in favor of his second family in England. She's loud, recklessly promiscuous and contemptuous of the tightly wound Sarah. Julie opens the pool and lolls about in various provocative states of undress, brings home a series of one-night stands of all shapes, sizes and ages — she's not particular — and leaves a whirlwind of dirty dishes and discarded clothes in her wake. But the women eventually reach a rapprochement, and Sarah becomes so intrigued by Julie's rootless and emotionally barren upbringing that she begins a second novel drawing heavily on Julie's confidences, even surreptitiously reading her diary to glean additional insights. Then Julie brings home Franck, creating an exquisitely uncomfortable situation from which Sarah decorously withdraws. When Franck fails to show up at work the next day, Sarah begins entertaining dark suspicions about what transpired after she went to bed. Ozon's cool sensibilities are a perfect match for French novelist Emmanuele Bernheim's elliptical screenplay; her elegantly untrustworthy narrative knits together clever psychological parrying and cliched mystery elements, then delivers an unsettling ending that casts the entire story in a different light. Rampling and Sagnier's prickly rapport is most ambiguous when it seems a bit obvious — there's always a revelation waiting around the bend.