Upper-crust decorum is stripped bare—well, unbuttoned a bit—in Separate Lies, a tale of adultery, redemption, and very bad driving. The directorial debut of screenwriter Julian Fellowes, it’s a miniature set in much the same world as his larger-scaled (and Robert Altman– directed) Gosford Park. The film opens with scenes of a bucolic Buckinghamshire village, including a bicyclist swooshing through the quiet—soon to be broken by the car that knocks him down and doesn’t stop. High-powered and -minded London solicitor James Manning (Tom Wilkinson), one of the hamlet’s weekend residents, isn’t very concerned about the hit-and-run incident, which turns into a murder case after the bicyclist dies. When his younger wife, Anne (Emily Watson), reveals that the victim is the husband of their housekeeper, he grudgingly pays attention. But the perpetually distracted attorney gets really interested when he begins to suspect that the errant driver was Bill Bule (Rupert Everett), a local cad with the laziest aristocratic mumble in the Home Counties. James’ hopes of undermining Bill are dashed, however, when he learns a few secrets, one of which is that his wife and Bill are having an affair. Hoping to salvage their relationship, James takes Anne to the picturesque Welsh seaside resort of Llandudno, where everything is as hushed and gray as the cuckolded husband himself. (Hint to Brits planning wintertime save-your-marriage trips: Think Mediterranean, not Celtic.) Anne agrees to stay with James, but it’s a promise she can’t keep, even before a final plot twist steers her into the sainted-whore mode that’s been a Watson specialty since Breaking the Waves. Adapted from Nigel Balchin’s novel A Way Through the Wood, Separate Lies is immaculately staged and performed, with Wilkinson a tower of hypocritical strength, Watson teetering deftly on the brink of hysteria, and Everett, actually doing something a little different for a change. As in Gosford Park, however, the mystery-plot contrivances merely distract from the naturalistic drama. Rather than reveal its tormented characters’ souls, the movie seems merely to be putting them through their paces. Both sociologically and psychologically, Separate Lies offers too much upstairs and too little downstairs.