Deng Cao, an angel intern who firmly believes that the world is full of love, meets Laharu, the demon prince who never believes in love. Deng Cao, who was going to assassinate the devil, learned that the devil was dead, so he changed his target and decided to assassinate Laharu. However, Deng Cao, who had great power disparity, was snatched away by Laharu. The important necklace given by Aziz to survive in the demon world can only stay with Laharu and is called a slave by him. The death of the demon king caused a commotion in the demon world, and everyone wanted to really seize the throne. The arrogant prince took his slaves and started to fight for the throne...