Unable to generate enthusiasm for anything since his wife’s death, retired physical therapist James P. Dandy has let his children cajole him into attending an Elderhostel at the Jersey shore. But the other participants seem indistinguishable except for their name tags and résumés—all but Dodee Swisher, a gallery owner determined to create her own laboratory component for their class in bonsai gardening. With Jim’s uneasy cooperation, she talks unsavory busboy Billy Dack into loaning them a shovel so that they can go illegally excavating some trees from city property. But things rapidly get out of hand when the Bolder Harbor police catch these felons in the act. The two end up comforting each other between the sheets back at the Windswept Dunes Motel, and they rise next morning to find Billy Dack fatally speared with the demonstration bonsai plant. Preliminary snooping indicates that Billy was a two-bit blackmailer, so Jim and Dodee ignore Detective Belinda Smith’s stern warnings to stay off the case and go after the blackmail tapes, with results about as surprising and dangerous as you’d expect for the Hardy Boys. A bonus in this winsome, if guileless, debut is a short course in how to style a bonsai plant and use it as a murder weapon.