Shigeyuki Honda, known as Peter, works from home as an illustrator while managing household duties as a homemaker. He lives with his girlfriend, Eri Todani, a living arrangement spanning two years since they met on a Hawaiian vacation. Honda feels a persistent lack of fulfillment in their relationship, stemming from his intense desire for marriage and children. This clashes sharply with Eri's focus on advancing her corporate career and her disinterest in starting a family. Their conflicting goals fuel recurring arguments, exposing vulnerabilities and past traumas affecting their perspectives.

As their relationship deteriorates, an external dynamic emerges through Honda's editor, Reiko. She begins questioning whether she might be a more compatible partner for Honda, given their differing priorities. This development forces Honda to confront a critical decision: pursue his deep wish for a family at the potential cost of his relationship with Eri, or accept her terms and remain together without marriage or children.