Mermaid Law

The mermaid clan has a rule: "All adult mermaids must go to the human world to experience life." The mermaid's tail can only turn into human legs when it reaches adulthood. The mermaid transforms into human form when it encounters water. It can only maintain its human form by carrying the water pearls given by the prophet. But an accident happened, and the eldest princess of the mermaid tribe suddenly lost contact...