Soo-yeong and Hae-soo are college friends who care for each other deeply, but they each harbor unrequited love for others: Hae-soo for Cha-moo, a senior by one year, and Soo-yeong for Dae-in, a senior by two years. On the other hand, Cha-moo and Dae-in both have feelings for Soo-yeong and Hae-soo, respectively, creating a situation where all four are interested in someone different. After a mismatched marriage, Hae-soo, who wants to get pregnant, actively seeks intimacy with her husband, Dae-in. However, knowing that he is infertile, Dae-in secretly approaches Soo-yeongs husband, Cha-moo, with a secret proposal.