Secretary Della Street is vacationing in Bolero Beach with her aunt, Mae Kirby. She becomes acquainted with "Blonde Bonanze" Dianne Alder, an attractive woman on a binge to gain weight quickly. Attorney Perry Mason is curious, and finds Alder has a contract with Harrison T. Boring, in which she is to gain certain weight in order to model some larger fashions. The contract has a curious stipulation that during the term of the contract, Dianne must share her income from all sources 50/50 with Boring. Mason is suspicious of that clause, thinking some is looking for Dianne to come into some money, and that the fashion reason is just a ruse. When Mason turns up some skeletons in Alder's closet, a murder occurs and she becomes the prime suspect. RM