No calories, maybe, but an awful lot of fat, as little old lady Angela Benbow and her friend, big old lady Caledonia Wingate, find out when they go undercover as a favor to Angela's friend Dorothy McGraw, whose Time-Out Inn is doomed to extinction if somebody doesn't clear up the mystery of who boiled Dorothy's assistant Jenny Adler in a hot tub. Dorothy's fat farm is a-waddle with suspects, and they all seem to be hiding promising secrets even before the police disclose that both Jenny and fellow victim Bunny Rogers were former prostitutes arrested one evening at the Kimbrough Hotel in San Diego (the same night the local cops pulled in a prominent unnamed California politician they found with Jenny). Overcoming their attachment to the Time-Out clients' meant- to-be-lovable tics, Angela and Caledonia eavesdrop on their liaisons and rifle their rooms for more evidence--at one point Caledonia rather endearingly imagines a confrontation with one suspect: ``We peeked into your checkbook and saw a huge deposit recently. Would you mind telling us if you're involved somehow in drug dealing?'' They uncover, well, mainly a red herring the size of Moby Dick. As in Murder by Owl Light (1992) and its brethren, suspicious behavior substitutes for mystery, and matey, good-natured bonhomie for wit.