With a brisk, early-morning walk around her home on Lake Tahoe, Tilda Swinton—the resolute heroine of Scott McGehee and David Siegel's elegant and suspenseful thriller The Deep End—begins a daily routine common to any middle-class housewife and mother of two. While her husband, a Naval officer, is away at sea, the responsibilities of keeping the family operating smoothly are entirely on her head, from the mundane chores of carpooling and laundry to the trickier management of her doddering father-in-law and moody 17-year-old son (Jonathan Tucker). So, when she discovers the body of her son's sleazy older lover (Josh Lucas) impaled on an anchor by the dock, Swinton's maternal instincts kick in and she treats it like just another everyday crisis, a spill that needs mopping up. Of course, covering up a presumed murder is not an everyday crisis, and neither is handling the blackmail threats of the victim's cronies, who demand $50,000 for an incriminating sex tape. The chief pleasure of The Deep End is watching Swinton try to integrate these extreme measures into her routine and maintain the appearance of normalcy, all while the danger and emotional stress leave hairline cracks in the façade. A Scottish actress known for her stolid, intelligent, exceedingly formal performances in Orlando and Derek Jarman's work, Swinton is an unusual choice for the role, but a perfect one, using minor facial expressions to register the fear and heartbreak just under the surface. Her presence steadies the occasional lapses in logic that mar an otherwise taut screenplay, which patiently turns the screws while examining strange tensions between the characters. Based on Elisabeth Sanxay Holding's The Blank Wall, a '40s suspense novel previously adapted by Max Ophuls for 1949's The Reckless Moment, The Deep End alters the dynamic significantly by changing the teenager's gender and sexual orientation. In addition to the obvious Oedipal undercurrents, the mother has yet to come to terms with her son's homosexuality, so her intense denial wedges a palpable space between them. More importantly, it puts a charge into her touching kinship with one of the blackmailers, beautifully played by the dark-eyed Goran Visnjic, who feels a grudging affection for her that's tangled simultaneously in motherhood and sexuality. McGehee and Siegel, who haven't directed a film since 1993's underrated neo-noir Suture, balance the suspense and dramatic elements with fluidity and grace. It's only after The Deep End is over that many of its unsettling truths come to light.