A male student's body is found at school. Authorities assume that the student killed himself in a fall. Other students at the school hold a trial to uncover the truth behind his death.

It tells an unpredictable 24-hour love story of the four-dimensional innocent girl Jung Saet Byeol who was once a troublemaker and the adorkable caring male store manager, Choi Dae Hyun, in the context of a convenience store. They have met each other accidentally 4 years ago, back then Saet Byeol asked Dae Hyun to buy cigarettes for them. Until now, Saet Byeol comes to the convenience store Dae Hyun runs for a part-time job, their hilarious romantic story starts.

On the first day of attending his new high school, Park Sae Roy gets into trouble after punching Jang Geun Won, who had been bullying a fellow classmate. Jang Dae Hee, the father of Jang Geun Won, is the CEO of the restaurant business Jagga, and the boss of Park Sae Roy father. After refusing to apologize for punching Jang Geun Won, Park Sae Roy father is fired, and he is ultimately expelled from school. Soon after, a tragic accident, caused by Jang Geun Won, takes place and Park Sae Ro Yoy’s father dies. Heartbroken and angry at his loss, Park Sae Roy viciously beats Jang Geun Won, earning himself time in prison. Deciding to take revenge upon the Jagga compony and the Jang family, Park Sae Roy opens his own restaurant in Itaewon, Seoul.

Although born in the same year, two childhood friends end up being 13 years apart because they have aged surprisingly at different places (worlds) for some strange reason. Now Eom Hyeon Soo is a 31-year-old woman but Sung Hae Sung is still a 18-year-old boy. Cha Won Yooung is a chef also interested in Eom Hyeon Soo.