While leading Xi Yan (Mermaid Yuechan) and Gu Ye (Water God) to meet, Father Time accidentally calculated that in the near future, mankind will have a devastating catastrophe, and the end of the world will no longer be a legend. The origin of this catastrophe can be traced back to the Ming Dynasty six hundred years ago. The Poseidon, who was suppressed in the abyss of the deep sea, has been holding on to it for tens of thousands of years. He turned his anger and resentment into a ghostly spirit and became obsessed with it. The possessed Poseidon escaped from prison and fled, determined to kill all living creatures in the world. The end of this catastrophe is Xiyan (Mermaid Yuechan) and Guye (Water God).
Under the guidance of Father Time, Xi Yan met Gu Ye. The two were boating on the river. That night was not the fifteenth day of the lunar calendar, but a full moon appeared in the sky. Xiyan felt something was wrong. She didn't want Gu Ye to see that she was covered with fish scales. In desperation, she stood up, but unexpectedly, a thousand waves arose in the river for no reason, and they fell into the river together, unconscious.
Resurfacing again, Xiyan found that she had traveled to the Ming Dynasty and accidentally broke into Manchun Tower. Fortunately, she was rescued by Jiang Xunfeng. Gu Ye also traveled to the Ming Dynasty and inexplicably became the second young master of Jiang Mansion and Jiang Xunfeng's younger brother, Jiang Yuze, while losing all his memory. The two met again in Jiang Mansion, but they didn't recognize each other.
Xi Yan, a modern girl, broke into the Jiang family's mansion and staged one ridiculous farce after another. The collision between modern and ancient times will always create sparks one after another. The appearance of the demon king Jiang Lingyun and Liu Ruxue, who does not eat the fireworks of the world, caused a lot of farce.
At the same time, the Poseidon, who was suppressed in the abyss of the deep sea, was already ready to move. His resentment and anger turned into ghost spirits, and the dark atmosphere shrouded the entire ocean, causing heavy casualties to the creatures on the seabed. In the end, Poseidon successfully escaped from prison and sneaked into the mortal world, thus kicking off his long-planned death plan.