Four years into their marriage, Nanami's husband Koji has just become independent and is busy with work, and perhaps due to a rut, the couple has not even been talking to each other lately. In contrast to the two of them, Hibiki, who moved into the room opposite, has a good relationship with her husband, and Nanami feels envious every time she sees the couple. Eventually, Hibiki finds out about Nanami and her husband's cold relationship, so she invites Nanami and Koji to her house and proposes a weekend couple swap...