Babson's 12th mystery has more geneological skeins than the Book of Genesis. Zita is painter David Fallbridge's second wife; Caroline, spoiled and irresponsible, his first. By her first marriage, Caroline had a daughter, Fanny. Now Caroline wants to marry gambling czar Xavier. To enliven the courtship, Caroline plans a cruise aboard her suitor's yacht and prevails upon the weak-willed Zita to babysit for Fanny, who is an obnoxious child. On the day David leaves for America, Fanny is kidnapped. Zita takes a trip up-Thames to recover the nine-year-old from Xavier, whose vengeance this is for Caroline's stealing a large amount of Xavier's ill-gotten gains. In a waterside cottage, Zita and Caroline find a murdered henchman but no Fanny. Eventually David, who suspects Zita of infidelities, resolves the situation by direct-dialing Scotland Yard from New York. Babson writes as though she is bored by the whole situation.