Two young women who share the same first name meet by chance on a train to Tokyo. Nana Komatsu, affectionate and impulsive, hopes to build a new life there with her boyfriend, while Nana Osaki, the singer of a punk band, wants to restart her career after leaving her hometown. Fate brings them together again when they become roommates in the same apartment. Despite their very different personalities and ambitions, a deep friendship grows between them. As their romantic, professional, and artistic lives become increasingly intertwined, the two Nanas discover the difficulties of adulthood, the sacrifices demanded by their dreams, and the fragility of the bonds that connect them.