Stacey—a lonely history grad student, at loose ends from a recent break-up and the death of her mother.

Branwen—a twelfth-century aristocrat, wife of one of Henry II's barons, alone in a castle full of people who barely tolerate her.

And then one day, the unimaginable. As a result of a past-life regression experiment gone wrong, the consciousnesses of these two women switch. Plunged into alien centuries, they must assume the other's identity, all the while fiercely guarding the secret of their own.

Follow their adventures as they learn, adapt, and fear what will happen if they are switched back ...