The late Ms. Gallant wrote for television, and this posthumous first novel does in fact read like an expanded TV script--in the Mystery Movie of the Week manner. Edith Weston hears of beautiful sister Karen's ""suicide"" in N.Y., so she heads home after ten years in Paris. Though the cops try to dissuade her, she's soon sleuthing away, falling in love with Karen's lover, ad-man Alan, who persuades her to capitalize on her resemblance to dead Karen to get the truth out of Karen's obviously guilt-ridden husband, rich Mike. With a nod to Rebecca and other worthy models, Edith survives hit-and-run, fainting spells, and fits of suspicion to distinguish between her sister's two amorous left-overs. Weak but inoffensive.