Lee Ji-hwan receives pictures in the mail that advises him of how he satisfied 2 women, Shim Su-in and also Kim Gyeong-heui, one summer 5 years earlier. He shares his memories with his friend Cheol-hyeon. He recalls at first being in love with Su-in, however she declines him. Throughout the summer, the 3 remain buddies. Ji-hwan and also Gyeong-heui create feelings for each and every other however are reluctant to confess. Ji-hwan recalls the facility connection between the three to Cheol-hyeon.