Crime, crisis get too close for comfort

Usually, “CSI: Crime Scene Investigation” is all about the evidence. This time it’s personal.

In a 90-minute episode tonight (9:30 p.m., CBS), a double homicide reunites Gil Grissom (William Petersen) with a spellbinding dominatrix, while a family crisis threatens to unhinge Catherine Willows (Marg Helgenberger).

Richard Lewis directed the episode from a script by Andrew Lipsitz, Ann Donahue, Anthony Zuiker, Bob Harris, Carol Mendelsohn, Eli Talbert, Josh Berman and Naren Shankar (talk about your forensic teams).

The almost-criminally entertaining main plot could be taken as an early Valentine’s Day salute, “CSI”-style. Grissom finds himself attracted once again to Lady Heather (Melinda Clarke) when he tracks two murdered male escorts back to her thriving lair, but cold reality sets in when she emerges as a prime suspect in the slayings.

Clarke is a delight as the perceptive kitten-with-a-whip, as is Elizabeth Berkley as another suspect, a brazen partygoer who would make Sharon Stone in “Basic Instinct” blush.

Amid all this, Willows must rescue her daughter (Madison McReynolds) after a mysterious car wreck, then nearly goes Sipowicz on a woman who was involved in the accident.

Tonight’s real draw, however, comes as Lady Heather peels away two of Grissom’s secrets, just enough to tantalize. “Are you losing your hearing?” she asks. “I’m losing my balance,” he replies.