Jeongyeon and Nayeon took three same courses during their second semester of college. They had little interactions and barely talked to each other. Jeongyeon developed a feeling towards Nayeon's chairmate, Mina, but Mina didn't even want to be close to Jeongyeon and hesitantly replied Jeong's messages everytime Jeongyeon asked Mina on something related to their homeworks. Jeongyeon then realized that it is stupid to approach Mina at the first place and that she should forget Mina, and surprisingly it's easy. Seems that Jeongyeon only had physical attraction towards Mina and that's it.

Right after they finished their final exam and summer break were about to start, Jeongyeon got a message from Nayeon, saying that she wish Jeongyeon to get good grades and to enjoy the long summer break. This is when the secret story began between the two of them.