Sung Chi-wook

Made half-human and half-spirit by accident, a young man is employed by a company of grim reapers in the underworld to carry out special missions.

A psychopath's ruthless serial murders have left the entire nation gripped by fear and chaos. An honest, justice-seeking rookie police officer and a veteran detective with a tragic past, face off against the killer. After their encounter with the psychopath, their lives change completely.

Kim Seo-Jin is a man who is driven only to achieve success in his life. Thanks to his efforts, he is the youngest executive at his company. His life is perfect, with his beautiful violinist wife Kang Hyun-Chae and a daughter. His wonderful life comes to a halt when his young daughter is kidnapped. He falls deep into despair. To change the past, when his daughter was kidnapped, he contacts Han Ae-Ri approximately one month in the past. Han Ae-Ri has busy days with her studies and working a part-time job to make enough money to pay for her sick mother's operation. One day, her mother suddenly goes missing. Han Ae-Ri falls into despair, when Kim Seo-Jin from the future contacts her.

Jo Jin-Gab was once a promising judo athlete. He protested against corruption at a game and he was kicked out of the sport. After that, Jo Jin-Gab became a gym teacher. Again, he could not control his anger against the son of the school's chairman. Jo Jin-Gab was once again kicked out of his profession.