Young Hallam Foe (Jamie Bell) is convinced that his stepmother (Claire Forlani) accelerated her upward trajectory from Dad’s secretary to Dad’s wife by offing Mom, but the coroner says it was suicide. An unswayed Hallam channels his grief and loathing into spying on couples going at it, Dad (Ciaran Hinds) and Stepmom primarily. After sleeping with the latter, he runs off to Glasgow, finds a doppelgänger for his deceased parent in Kate (Sophia Myles), and sets about spying on her in the bedroom. These are unlikely components for a comedy—which Mister Foe, against the odds, definitely is. Co-writer/director David Mackenzie has jokingly claimed this as the capstone of his “sex trilogy” (2003’s mostly celebrated Young Adam and 2005’s mostly ignored Asylum preceded it), a threesome (har) of films extrapolating a single idea: In Mackenzie’s world, wholesome sex is a possibility for other people, but never for the (anti-)hero, whose couplings are always the sublimated expression of something else. What makes Mister Foe such unlikely fun, though, is Bell’s accomplished smart-ass routine and Mackenzie’s blithe attitude toward taboos. Every possible voyeuristic/incestuous kink gets a workout. “I like creepy guys,” Kate declares, but she doesn’t know the half of it.