Tempted by thoughts of a vacation in an exotic Spanish locale, governess Dinah Haversham comes to the ancient Castle Estillio as the guest of rich scientist Max Hind and his vapid sister, the Contessa Julia Ascoli. But when their entourage arrives at their destination, Dinah is inexplicably spooked. Why would Julia leave her friends and her seaside villa for this desolate place, with only her eccentric brother, two boisterous little nephews, her lover and a handful of servants? Dinah will soon learn that her instincts don't lie. There's the bizarre tower turned into a modern laboratory, a sinister dungeon full of macabre instruments, and the handsome stranger Dinah is afraid to trust. All would become essential to a madman's plan for a self-styled apocalypse . . .