When cat spirit Luo Xiaohei's home is deforested by humans, he must find a new one. He runs into a group of other spirit creatures who take him under their wing with dreams of reconquering the land they say is rightfully theirs. However, they run into a human known as Wuxian who separates Luo Xiaohei from the other spirits and the two go on a journey, with the cat spirit learning to control his abilities as well as forming his own thoughts on whether or not he should ally with the spirits or the humans.

The Primus extracts a Mixed Yuan Bead into a Spirit Seed and a Demon Pill. The Spirit Seed can be reincarnated as a human to help King Zhou establish a new dynasty, whereas the Demon Pill will create a devil threatening humanity. Ne Zha is the one who is destined to be the hero, but instead he becomes a devil incarnate, because the Spirit Seed and a Demon Pill are switched.

Two boys meet at an opera training school in Peking in 1924. Their resulting friendship will span nearly 70 years and endure some of the most troublesome times in China's history.