Swap wives with your next door neighbor to find new feelings

In the 4th year of marriage, Nanami's husband, Koji, has just become independent, busy with work and busy, recently even the couple's conversations have stopped. In contrast to these two, Hibiki, who had moved to the opposite room, was very kind to her husband, and whenever she saw the couple, Nanami felt jealous. Finally, Hibiki, who has learned about Nanami's cold marital relationship, invites Nanami and Koji to her house and proposes a weekend-only couples exchange.