Maria is the daughter of an unmarried woman who works at a seaside resort hotel run by relatives. She is close to her two female cousins, one of whom, Tsugumi, has suffered her entire life from an unnamed illness. Tsugumi is mean-spirited, antisocial, and cruel, and Maria is often the only person who can get through to her. When Maria's mother finally marries her father, he takes them away to Tokyo, where Maria begins college and a tenuous new social life. She returns to the seaside resort for one last summer before it is to be sold and discovers that the lives of everyone there, especially Tsugumi, have changed.