Hwang Hyunjin is a guardian angel, and he has a lot of status in heaven. Until, the human, a little girl, dies early from cancer. He failed to protect her. He got banished from heaven, and has been sent to hell to be a fallen angel. In hell, fallen angels are really powerful and extremely rare, the last one got sent there 2 millennia ago. What will happen to the vengeful Hyunjin when he can’t let go of the grudge he took with him to hell..?