It tells the story of the demon king and the unlucky princess as they weave through memories of the past in a collection of books. With a mission to complete, they experience the love and sadness of various spirits and monsters. Chun Yao used to be an immortal tasked with guarding the monsters in Wangchuan. He is banished from the heavens for committing a mistake and becomes the king of all monsters in Hundred Spirits Lake. When princess Han Sheng of Bailu Kingdom enters the lake, she discovers that she is carrying a book that only monsters possess. The arrogant Chun Yao has no choice but to take her along in an adventure to seek the mystery behind the books which leads them to uncover many stories: Daoist monk Bu Fan meets Bai Shan , a temptress who steals the life span of women to prolong her husband's life. Kong Qi who silently guards his beloved and the god of war Xiao Shan face a trial in love and come to realize the importance of cherishing the person before you. Shen Ci is a mermaid who falls in love with Xie Changye , a hostage of Beilu Kingdom. She voluntarily endures the pain of removing her tail to become his aide, yet they are caught in the power struggles around them. Wu Gen who was formed from the water of Guanyin is sent to raise Si Tong . After Si Tong grows up, Wu Gen must destroy him along with the devilish miasma of the Sprite Abyss but starts to form a strong bond with Si Tong as his father and his teacher.