In this world, there are three dominant species. Humans, weak and unable to protect themselves. They live on Earth. Angels, they protect the weak and bring joy to others. They live in Heaven And demons. They attack the humans, feast on them. They're everyones nightmare. They live in hell. Lee Heeseung is the son of the ruler of the demons. He's been brought up to hate angels and humans, like the rest. The demons have been trying to take control over the whole world for many centuries but the angels have the power to completly stop them. So the demons formed a plan to get inside and gain control. Heeseung was chosen for this mission. He was disguised as a high school angel. His job was to try get information about anything the demons could use against the angels.

Heeseung entered the school for his first day, masking his hate as he moved through the bright halls filled with angels. Turning a corner, he bumped into someone, her books scattering to the floor. She looked up, her radiant presence momentarily stunning him. His irritation flared, and his eyes glowed faintly red before he quickly looked away, forcing the glow to fade. “Sorry about that,” he said, feigning a smile as he helped her pick up her things.