Everything has to go according to fate. People die when they die, people live when they live. Nothing gets tampered with, or things will go very, very wrong. When Heaven receives a vision of an explosion that will end all life on earth, the angels are convinced they should eliminate the human responsible for this future disaster. However, one angel disagrees: Celeste believes that a certain demon is projecting this vision in order to cause chaos. Unfortunately, due to her past with said demon, she is cast out of heaven for allegedly acting on emotion instead of logic, before she can argue in addition that killing the human is completely against all their rules about the divine interfering with a life’s fate. Now on earth, without the power to get back to heaven, Celeste follows her gut. She doesn't know if she's right to protect this human. Yet, as Celeste spends more and more time with the human, she discovers that doing the right thing might not be what she thought.