After serving his military duty, Jung-hoon, who has never had a girlfriend, returns to college. He has a secret crush on Eun-ji, a member of the school's paranormal activity research club called Mysteria, in which he also belongs. One day, Jung-hoon meets Ji-sun, a virgin ghost, by chance, and Ji-sun asks him for help with her Scare tests, the exams that she needs to pass in order to be reborn. In return, Jung-hoon makes an arrangement with Ji-sun to help him score points with Eun-ji. While trying to help each other's problems, the two run into disagreements, but their feelings for each other grow deeper as time passes.

Se-hyun, who had a car accident three months ago, is preparing for the World Climbing Competition. She suffers from nightmares due to her unrecoverable condition and pressure on competition. Then one night, a phone call is made to Sehyun's cell phone, which was broken at the time of the accident.