Flawed but promising: a debut crime/caper novel featuring an innocent-bystander hero, a con-woman heroine, two sets of psycho-villains, and a plot that veers uncertainly between the overly contrived and the crudely simplistic. Charlie Gamble, living on a sailboat in the Boston Harbor marina, is a divorced loner, a dropout from computer-sales, doing boat repairs--when mysterious beauty Rosy Marlette, a waif in a red Ferrari, enters his life. Unbeknownst to Charlie, however, Rosy is a sexual scare artist who attracts rich men, persuades them to buy her expensive jewelry (from her own crony-jeweler), then dumps them. So when a hired hit-man launches assaults on Charlie's boat, he has no way of knowing that Rosy has been targeted for vengeance by one of her bygone scam victims (a psycho-doctor). Furthermore, when Rosy then disappears, Charlie has no way of knowing that her latest scare has gone grimly awry--landing her (just by chance) in the clutches of a sadistic, psychopathic ex-con. Nonetheless, ingenious Charlie manages to track Rosy down--not only rescuing her in a gory shootout, but also arranging (with lots of help from coincidence) to dispose of that vengeful psycho-doctor. Rosy's drawn-out ordeal with the sadist-psychopath (involving murder, robbery, rape, torture) too often reads like exploitational pulp-melodrama. Charlie's transformation into a clever, fearless, violent super-sleuth--like the overstuffed plot--is less than convincing. But Matheson's storytelling is bright and springy (especially in the first half), the varied Boston backgrounds are well-sketched--and hero Charlie, little more than Travis McGee clone here, might take on more distinction in subsequent adventures.