Ess's mother, Vivian, left her a rose made of the same crystal that formed the Great Machine, which allowed the Originators and Revisionists to travel through time. A matching rose belonged to her friend, Anna, and the two women communicated mind-to-mind, until Vivian died. When Ess was too young to understand, she touched minds with Carmen, Anna's daughter, through the crystal rose. Both girls thought the other was merely an imaginary friend. ...