As Mira Morales and her teenage daughter, Annie, prepare to return via motorboat to their home in the Florida Keys, Mira is knocked unconscious and Annie is kidnapped. After regaining consciousness, the psychic Mira tries to locate her daughter, but when her boat glides through Florida's "black water," she travels back in time to 1968. Meanwhile, Annie's kidnapper, the germaphobic Patrick Wheaton, drags her through the same "corridor." Through the investigative work of FBI agent Wayne Sheppard and the psychic bond that Mira and her grandmother Nadine share, the reasons behind Wheaton's actions unfold, and the story becomes even more unsettling. The constant shift between the past and present may confuse readers, especially as events unfolding in the past begin to affect the present. Though some may find the book's paranormal elements hard to swallow, MacGregor skillfully builds the tension to a heart-pounding conclusion.