Soufuu Sou's dream is to find a good partner and start a family. And in the academy, there's a club to help achieve that dream: the Childbearing and Pregnancy Preparation Club. The Childbearing and Pregnancy Preparation Club is a nationally recognized club activity that encourages student pregnancy and supports pregnancy preparation. Sou was able to join the club after selection. There are two girls who wish to be his partner: Touno Umi and Asagi Aika. He can only choose one partner, and he must decide within a one-week trial period. The trial period is a time to have sex to check physical compatibility and each other's feelings. Umi and Aika take turns spending the trial period with Sou, one day each. Sou finds himself developing feelings for both of them, and he feels their affection for him as well. As Sou worries about hurting either of them, the days of the trial period continue to pass.