The story takes place in "Jiuyuan", an imaginary dynasty where strange beasts and human races coexist with mountains and seas. The heroine Zhu Yao is an orphan girl who was abandoned in the mountains, but she actually carries the "bloodline of Zhulong". The source of spiritual power in this world comes from the mysterious mountains and rivers recorded in the "Book of Mountains and Seas". People of different bloodlines can establish contracts with specific alien beasts. In the dynasty, the "Shan Hai Division" is a mysterious organization responsible for supervising the balance between alien beasts and humans. The male protagonist Si Xuan is the current head of the Shan Hai Division.
