Dahyun and Sana (you) were starting to be friends until Dahyun became friends with the group that bullied Sana. Everyone knew that Sana liked Dahyun, even herself, but she didn't care, she was interested in Tzuyu, the worst of all and the most cruel.

After an accident, Tzuyu needed a heart transplant. Sana, after being completely depressed and without the slightest desire to live, decided to donate. Dahyun was heading towards the waiting room where you were, she entered.