One day, Liu Hai unexpectedly finds a beat-up book of magic. When she tries to draw a magic circle from the book, she accidentally summons a monster girl named Chi Xiaoliu. Xiaoliu has been imprisoned to provide the source of power for the Kingdom of Chi. She had wanted to escape for a long time and finally succeeded in escaping, just as Liu Hai was drawing the magical circle in the human world… and that's how the two girls met.

(Source: Bilibili, translated)