Yaya forces Yuechu to cooperate by freezing and throwing him around with her superior spirit power. Rongrong mentions how the Ehuishou controlling the spirit strings was the one that possessed Wang Fugui and was defeated by Yaya before. Yaya previously tried to use a different beast but not cooperating, she froze it (this is the frozen beast she showed Wang Fugui Yeye in Episode 18).
Meanwhile a strange woman back in town laughs to herself about having planted a different secret Ehui Shou. She uses voodoo like sorcery to remotely mutate and control the Disaster Beast and thus Yuechu via the spirit strings. The voodoo woman controls and releases the power hidden with Yuechu.
The controlled Yuechu causes the skyscraper to explode sending rubble everywhere. Qingtong protects Fugui. In doing so, Bai and the beast turn zombie green. After seeing his power, people are sure that Bai is indeed the reincarnation of Dongfang Yuechu.
Rongrong and Yaya realize that the Nanguo Princess is causing trouble manipulating Bai remotely. They send agents to find the Nanguo Princess, but she has left many decoys around Tushan to throw them off--signature Nanguo witchcraft.
Yaya attempts to use her older sister's special Spirit Expelling Technique (驱魔一式 Qumoyishi). She punches Bai in the stomach, and this expels the green ehuishou out of Bai. But this causes the South Princess' trap to go off. Bai then turns demon red and is possessed by a more insidious spirit that the princess planted earlier within Yuechu.
The Nanguo princess reveals what she did: in previous episodes, when Wang Fugui was flirting with women, she put a demon in his drink that caused him to be possessed by an ehuishou. Later she put a demon in the poisoned bun that Bai Qiuen used to trap his son. This demon is special in that absorbs yaoguai energy from the outside to grow. So when Yaya used Qumoyishi on Bai, the demon absorbed the energy to continue controlling Bai.
The Nanguo princess escapes, while Yaya is left to defeat the demon within Bai.