Li'er comes from the world of demons. For some reason, the demon king sent her and her brother to the human world. A few years later, Li'er's magic skills improved a lot, but the demon world was in great trouble. Li'er's secret is hidden in the crystal. When the crystal breaks, the dust-laden memories are awakened. Just when he was about to fight against the devil with all his strength, he fell hopelessly in love with a devil...