If Hitchcock had made What About Bob?, this engrossing and blackly funny French psychological thriller would be it. Thirtyish Michel (Laurent Lucas: La Nouvelle Eve) is on a car trip with his wife, Claire (Mathilde Seigner), and three preschool daughters when he runs into an old school chum, Harry (Sergi López), in a roadside restroom. At least, Harry says he’s an old school chum — Michel doesn’t remember him at all. But when Harry and his scarily adoring girlfriend, Plum (the luscious Sophie Guillemin), invite themselves along to Michel’s ramshackle summer house… in the middle of nowhere… it becomes clear that Harry is who he says he is, and that just makes him all the more frightening. Why on earth would he have memorized a juvenile poem Michel wrote for the school literary magazine two decades earlier? Why is he so concerned now — as he sees Michel and Claire, in their mundane domesticity, down to their last nerves with each other — for Michel’s “happiness”? Why won’t he just leave? In fine Hitchcock fashion, the house becomes as much as character as any of the people onscreen, sighing its noises — the rattling of the fridge, the buzz of the fluorescent lighting — between Harry’s mysterious, obnoxious pomposity, Claire’s fed-up-to-hereness, and Michel’s bewildered befuddlement as he treads a delicate path between them. Yes, it’s a French film, but don’t let that scare you off — it isn’t terribly French (except for the bit with the eggs — that’s pretty French, and pretty funny). The film’s score parodies suspense music, oscillating strings trilling with every ominous shot of night descending upon the remote house. And when Harry asks, of the old well in the yard, “Is it deep?,” you’ll chuckle with grim recognition. As Harry’s attempts to ensure Michel’s happiness escalate, the depth of the well will be well plumbed. But you already knew that… and that doesn’t decrease the morbid fun here one whit.