Taika Inaba, a young man working for a video game company, has a deep wish for his grandmother to meet her great-grandchild. His path to starting a family, however, is blocked by a secret he carries: erectile dysfunction, a condition that has caused past relationships to fail. At a speed-dating event, he unexpectedly connects with Ayano Katase, a doctor who is forthright about her own urgent desire to have children. Just as the couples are about to be announced, Taika’s anxiety gets the better of him and he flees.

In an ironic twist of fate, Taika later visits a clinic to seek treatment for his condition, only to discover that the attending physician is none other than Ayano. During the examination, a startling revelation comes to light: his physiological problem vanishes completely when he is with her. Recognizing this unique compatibility, the pair enter into a secret, contractual marriage. Their single, pragmatic goal is to conceive a child within one year, a timeline that also aligns with Ayano’s requirement to become a parent in order to inherit her family’s hospital.

The story follows Taika and Ayano as they navigate the complexities of this unusual arrangement, moving in together and trying to balance their clinical objective with the development of genuine romantic feelings. The situation is complicated by the presence of Mimi Kagamiya, Taika’s cheerful junior colleague at work who harbors hidden feelings for him, leading to moments of romantic tension and misunderstanding.

As the contractual year progresses, the couple faces the emotional ups and downs of their endeavor. Despite their efforts, they experience the disappointment of failed pregnancy attempts, which forces them to confront whether their relationship is merely a means to an end or something more substantial. Key narrative arcs include their initial decision to form the contract, the challenges of keeping their marriage a secret, and the gradual shift from a transactional partnership to a sincere emotional bond, ultimately culminating in a reevaluation of what they truly want from each other.