Sabine lives two lives. Literally. Each night, at midnight, she ''shifts'' from one self to another. Time resets too; Sabine may be a teenager to her families and friends but in reality, she has thirty-odd years-worth of life experience. It's a stressful existence: the shift itself is frightening and painful, and Sabine must be careful to behave appropriately in each environment. And her lives are very different. In Wellesley, Sabine is wealthy and popular with two brothers and a boyfriend other girls are jealous of. In Roxbury, she has one sister, parents whose business is struggling, and a reputation for rebelliousness.