Charlotte Rampling spends the first scenes of Swimming Pool wrapped so tightly in a raincoat that it's clear she'll eventually either loosen up or suffocate. The London-based author of a successful mystery series, she lacks neither fame nor fortune, but there's a void in her life that all the breakfast whiskey in the world can't fill. Re-teaming with his Under The Sand star and working again with Sand co-writer Emmanuèle Bernheim, director François Ozon takes a plunge into that void with his own take on the psychological thriller. To help Rampling along, or perhaps just to get her out of his hair, publisher Charles Dance sends her on vacation to his summer home in southern France. The unfamiliar scenery seems to do the trick, as Rampling replaces alcohol with Diet Coke and rich food with yogurt, and settles in for long writing sessions overlooking scenery marred only by the presence of a neglected swimming pool. Then someone comes to end the neglect. Frightening Rampling in the middle of the night, Dance's previously unmentioned college-age daughter Ludivine Sagnier arrives to set up housekeeping, sleep with anyone she chooses, smoke, drink, and, of course, swim. What begins as a funny two-person variation on The Real World finds the murky terrain that Philippe Rombi's Bernard Herrmann-meets-Ennio Morricone score announces from the start, as Rampling starts to view her unexpected housemate as a subject for her work rather than a distraction from it. As the well-matched, equally tough-minded Rampling and Sagnier get to know each other better, Ozon keeps ratcheting up the tension and letting it go, allowing them to circle each other menacingly, become friends when they realize how much they have in common, and then resume circling. The tangle of opposites would risk getting too knotty, if not for Ozon's sense for the intricacies of his characters, and for camerawork and editing so economical that it's tough to find a wasted second. Swimming Pool returns Ozon to the psychological complexities of Under The Sand and his early mini-feature See The Sea, and he again proves himself a master of building shocking moments from a series of seemingly insignificant gestures and throwaway lines, and unsettling mysteries from everyday ambiguitiesand then reducing them back again, creating a deeper mystery still. By Swimming Pool's end, Rampling has taken a swim, found her authorial inspiration, and ditched the raincoat, but the whys and the hows remain as confounding an enigma as any she could hope to write about.