On a cruise ship between Algiers and Venice, Martin Boyne, an unmarried engineer in his forties, encounters a wild, ebullient menagerie of stepbrothers and sisters, kept together as a `family' by the efforts of the eldest, the lovely, fifteen-year-old Judith. Caught between genuine outrage at the plight of the precocious and fought-over children and his disturbing feelings for their fifteen-year-old sister-protector, Boyne finds himself increasingly drawn to their enchanting, improper and liberating ways.