When Jo Gang-Ja attended high school, she was notorious for fighting. She gave birth to her daughter A-Ran in her late teens and became more responsible. Her daughter A-Ran is now a high school student, but A-Ran is bullied at school. Jo Gang-Ja decides to go back to high school to protect her daughter. Jo Gang-Ja becomes a high school student again.

Choi Jun-woong seeks a job, but it's hard for him to get hired. One night, he witnesses a man trying to end his life and decides to stop him. He gets acquainted with grim reapers Koo Ryeon and Lim Ryung-gu, who belong to a crisis management team. Their purpose is to prevent people from committing suicide. After Jun-woong ends up in a coma and becomes half-human and half-spirit, he is employed by a company of grim reapers as the newest member of the crisis management team.

Woo Ah-Jin lives a luxurious life due to her wealthy father-in-law, but her father-in-law's finances become decimated and her husband betrays her. Woo Ah-Jin's life hits rock bottom. Park Bok-Ja is a mysterious woman and she hides her heartbreaking story. She brings about fierce hardship on Woo Ah-Jin.