R City is a coastal town that is isolated from the world all year round. The residents of the town make a living by fishing. Qian Yu has lived here for 19 years and never left. One day he went to sea with his father and encountered a storm. His father's whereabouts were unknown and Qian Yu was swept to D City by the waves, where he met Li Junyang.
People in City D call City R "Atlantis". While trying to get home, Qian Yu accidentally discovered that there was a wall hundreds of meters high outside R City. With the help of Li Junyang, the two secretly returned to R City. Junyang discovered that something had entered R City unknowingly, but Qian Yu knew nothing about it.
Purpose: Protect the environment