Every Day is the story of A, an undefined entity/being/soul that wakes up every morning in a new body, basically supplanting the being that the body belongs to. It has always been this way, since A can remember–A has no body of its own, no family, no true identity. A does, however, have its own thoughts and feelings and even its own email address that it uses to keep track of the bodies its inhabited and the things it has experienced. For the most part, A just floats along and does its best to not disrupt the lives of the people it inhabits, until one day it wakes up as Justin, a teenage jerk who just happens to have a beautiful, near-perfect girlfriend, Rhiannon. A falls in love with her, and the rest of the novel is its attempt to preserve that relationship and keep her close while still shifting from body to body.