The Scottish actress Tilda Swinton has ghostly white skin, lank hair, and the delicate yet severe face of a perturbed-looking Victorian doll. It would be hard to think of a performer more austere, and when Swinton first came to prominence, in avant-feminist tracts like Orlando, she used the chilliness of her looks didactically. But in The Deep End, she plays a ''normal,'' domesticated American -- a mother, no less -- who tries to cover up a murder, and you can feel the zest with which she bites into the middle-class blandness of the role, and the anger beneath it, too. For the first time, Swinton as an actress seems truly liberated.
The main setting is a poshly cozy home along the woodsy waterfront of Lake Tahoe, where Swinton's earnest mom is doing everything she can to stop the clandestine sexual relationship between her teenage son (Jonathan Tucker) and a 30ish sleazeball (Josh Lucas) who co-owns a nightclub in nearby Reno. One night, there's a rendezvous, then a scuffle; the next thing Swinton knows, she's discovered the nightclub owner's corpse lying at the water's edge. Desperate to hide what she presumes is her son's involvement, she sinks the body into the lake, at which point she might as well have committed the murder herself.
For a while, The Deep End lures us into a pleasurably old-fashioned web of guilt, treachery, and logistical cunning. That said, virtually nothing that happens is entirely plausible, from the gruesome coincidence of the corpse's first appearance to Swinton's face-off with the dead man's associates, who employ a sexual videotape of her son to blackmail her for $50,000. As the henchman, sent to shake her down, who sort of falls for her (at least, I think that's what happens), the charismatic Goran Visnjic is playing a thug with a heart of gold. Codirected with visual menace by Scott McGehee and David Siegel, The Deep End displays a promise it doesn't, in the end, live up to. See it for Swinton's embodiment of unadulterated maternal will.