Fifteen-year-old twins Sandy and Dennys are the practical members of the Murry family. Unlike their siblings, Meg and Charles, they have never experienced a journey through time or space. But when, overcome with winter doldrums, they type "TAKE ME SOMEPLACE WARM" on their physicist father's computer, they are suddenly whisked away to biblical times.
Here, the fallen angels vie for control of Earth with the seraphim, and a diminutive patriarch named Noah has received a mysterious message from El to begin building a huge ship.
Sandy and Dennys must find a way to return to their own time before the flood begins, but they are concerned for the fate of Noah's beautiful granddaughter, Yalith, who is not mentioned in the biblical account.
Forced to think independently for the first time, the twins affect history in ways they couldn't have imagined, learning that "some things have to be believed to be seen."