Gwyneth Shepherd's sophisticated, beautiful cousin Charlotte has been prepared her entire life for traveling through time. But unexpectedly, it is Gwyneth, who in the middle of class takes a sudden spin to a different era! Gwyneth must now unearth the mystery of why her mother would lie about her birth date to ward off suspicion about her ability, brush up on her history, and work with Gideon--the time traveler from a similarly gifted family that...

Sixteen-year-old Gwen, the newest and final member of the secret time-traveling Circle of Twelve, searches through history for the other time-travelers, aided by friend Lesley, James the ghost, Xemerius the gargoyle demon, and Gideon, the Diamond, whose fate seems bound with hers.