What do you do with a mystery plot that's going nowhere? Have the detective--here it's familiar Knut Severson, Chief of Police in Wellesley, Mass.--kidnapped halfway through by a psychotic little old lady (she chains him to the wall) and then bopped by the little old lady's chained-up sister, who's only semi-psychotic. (Possessive, puritanical Papa drove them starkers.) Arsenic and Old Lace without the laughs (though a pornographic snowman may provide a chuckle) is less than Knut & Company deserve; the likable small-town crowd includes Knut's shoplifting secretary, an overactive alderman who disappears (one of the sisters' victims), and a poetry-writing babysitter. Pitiful story, palatable surroundings.