Lovesey moves from Victoriana (the Sergeant Cribb series, Waxwork) to 1921 -- with a sly, sprightly, pseudo-true-crime diversion that's easy to see through but impossible to put down. A prologue offers two teasers: who is the passenger aboard the N.Y.-bound Mauretania who, posing as legendary Inspector Dew (Dr. Crippen's nemesis), is investigating a shipboard murder? And how is Charlie Chaplin -- on a 1921 visit to London -- going to figure into this story? (The chapter titles are borrowed from Chaplin films.) The first teaser is soon explained -- as we meet Waiter Baranov, a London dentist whose domineering rich-actress wife Lydia is determined to revive her flagging career with a move to Hollywood; Waiter's appalled. . .and turns to adoring patient Alma Webster. Together they hatch a Crippen-esque plot: once Lydia is aboard the Mauretania, Walter will push her out a porthole and Alma will thenceforth impersonate rich Mrs. Lydia Baranov! And so it goes. . .or does it? We never actually see Walter dispose of Lydia (though she's certainly gone). And then a body is fished out of the water -- but it's that of strangled Katherine Masters, the distaff half of a husband-and-wife card-sharp team. So Walter, who has whimsically chosen the Dew name as his shipboard alias, is mistaken for the detective; and when asked to do the sleuthing, he eagerly (1) complies. Who killed Katherine? Did Walter kill Lydia? And how will assorted romances turn out? The answers are neat, if not surprising (with a Christie-ish chill to the Katherine murder-motive); the period touch is gin-and-tonic light; and we dare you not to smile and smile again as wicked entertainer Lovesey sails through each roll and turn of the transatlantic crossing.