Nora and Blanche are conjoined twins. Nora is strong, funny, and deeply independent, thirsting for love and adventure. Blanche, by contrast, has been asleep for twenty years. Sick of carrying her sister's dead weight, Nora wants her other half gone for good—a desire that takes her from San Francisco to London in search of the Unity Foundation, a mysterious organization that promises to make two one. But once in England, Nora's past begins to surface in surprising and disturbing ways, pushing her to the brink of insanity and forcing her to question her own—and Blanche's—grip on the truth.