The various faces of youth and people in an enclosed space of a convenience store for 12 hours.

Hee-Soo (Kim Sun-Young) is a popular songwriter with numerous hits, but she is going through a dry spell. She wonders if she lost her inspiration, because she is lonely. Hee-Soo then meets a boy (Byun Joon-Suk) in the elevator of an apartment building. She notices his stares. Hee-Soo feels a new song coming about. On the pretext of giving the boy music lessons, Hee-Soo gives the boy a lesson in love. As time passes, the boy falls for her more and more and Hee-Soo’s song is almost completed. At this time, Joon-Ho, who taught her about love and music, returns.