As in The Minden Curse (1978), eleven-year-old Danny Minden seems to turn up where ""funny things happen"" (such is the curse); and though few of them would occur outside a juvenile mystery, they do pose some real problems for Danny and bouncy C.B. (Clarissa Beatrix), his fellow newcomer in town. Somebody is out to make it appear that elderly Cat Ladies Rosie and Anna Caspitorian are too incapacitated and irresponsible to remain in their old castlelike house--where everyone believes their father stashed away a pile of money. Danny's come to know them and like them, so he's concerned; but he has a special interest in ingratiating himself because he's been set the near-impossible task of capturing the sisters' most formidable cat, ""Killer,"" as his initiation into the fifth-grade boys' Secret Club. So when Miss Rosie is hospitalized after another ""accident"" and Danny is invited to stay with Miss Anna, he welcomes the chance to thwart both the Caspitorians' nasty nephew and their oily neighbors--whose ends (if not means) even the sisters spot--and the chance to bag Killer. Tripping up the money-seekers turns out to be less difficult than netting Killer, who ups and disappears. And why do the sisters, who've assured Danny they have resources nobody suspects, speak of the cat in the same breath? Danny has a flash: the cat's fancy collar--a sign, to some, of the sisters' irresponsibility--might contain real diamonds (he's right); and he has a shock: the cat was overpowered and hidden and left for almost-dead by Danny's nemesis, the club bully. The windup finds the sisters spared further harassment and Danny opting out of the club: it was wrong to think of capturing Killer in the first place. Roberts needn't have had all the other kids follow his lead, but the cat aspect gives this some gut-interest that neither the sisters' familiar predicament nor the transparent villains provide.