Lexi Archer is a teenager who, after the divorce of her parents, moves with her mother Kathryn and younger sister Jill from Chicago to Seattle. At her new school, she befriends Jennifer Harnsberger, a popular straight A student whom she meets during volleyball tryouts. After her volleyball coach suggests that Lexi should lose a few pounds in order to enhance her athletic performance, she starts to look for ways to diet. When Jennifer admits to being bulimia nervosa, they decide to dieting and work out together.