Discovering the 300-year-old skeleton of shipping tycoon Jedediah Biddeford in the ballroom wall is a big old hassle for Josie Waters, owner of the Oyster Cove Guesthouse. Especially when Biddeford's descendants turn up, certain that a family legend about treasure buried nearby must be true.   Josie is too busy dreaming up the perfect cake for the Oyster Cove's 250th anniversary celebration to worry about the Biddeford family --plus half the town -- digging up her yard... until one of her guests is murdered in the guesthouse garden.   With worries that her guesthouse will get a reputation for being the kind of place you only leave in a body bag, Josie must put her detective skills to work to find the killer. Lucky for her, Nero and Marlowe and their gang of cat sleuths are also on the case.   From the old wharf, to the town common, to the guesthouse itself with its many nooks and crannies, the cats are sure to sniff out the killer... but can they help Josie stop the person behind the mysterious murder before they strike again?