Nayoung is secretly in love with the campus sweetheart named Kim Sejeong who's also her bestfriend since grade school days. Nayoung knows that they are in a one-sided love situation cause Sejeong has a big crush on the pretty transferee named Hana. But what will happen if Nayoung finds out that Hana is her secret admirer that always put a love letter in her locker?