
Lee Seul Bi is an angel who is sent to Earth to look after Shin Woo Hyun, who lives with his grandmother and carries emotional scars from being abandoned by his parents. Despite his cold demeanor, Woo Hyun is popular in school because of his good looks and singing ability. When his best friend, Hwang Sung Yeol, finds out a secret that ties them together and also develops feelings for Seul Bi, who is posing as a fellow student at their school, the best friends turn into rivals.

L, an angel who’s endlessly fascinated with the human world, gets into trouble when she unthinkingly saves the life of Han Shi Yeong, a man who was meant to die. To make up for her mistake she must guard him on Earth for one hundred days and keep him safe from Hwan, a death god who is required to collect his soul. Both supernatural beings must contend with the knowledge that whichever one of them fails by the end of the hundred days will be erased from existence, and the longer they stay on Earth the further their powers fade and the more human they become.