In order to find out why his wife was killed, Chen Zheng, the general of Zhenhai, has been tracing a mermaid, but while doing so, he accidentally discovered a conspiracy in North Korea.

Ariel must turn back into a mermaid to go into the sea once more to find her missing daughter. However, Ursula's crazy sister, Morgana, intends to take control over the entire ocean. Ariel and her ...