The queen of the human tribe gave birth to twin girls. Respected by the entire tribe, the older sister Qing Kui, who is gentle and kind, is betrothed to the heavenly prince. The younger sister, Ye Tan, smart and cunning, shunned by her own people, is betrothed to the demon prince. Due to a mix-up, the two sisters are married off to the wrong husbands. It paves the way for two beautiful romances and also ignites a conspiracy that shakes the four realms.

Taishi Wen Zhong led the army of Shang Dynasty including Deng Chanyu and four generals of the Mo Family to Xiqi. With the help of Kunlun immortals such as Jiang Ziya, Ji Fa led the army and civilians of Xiqi to defend their homeland.

Hu Bayi and Fatty Wang had planned to go abroad with Shirley Yang. However, they were entrusted by Professor Chen to travel to the Coral Spiral with Mr. Ming to search for the Qin Emperor's Bone Mirror. They befriended Ruan Hei, Gu Cai, and Duo Ling on Coral Temple Island. Together, they set sail. One night, they were sucked into the underwater cave of Guixu.