Mamori, an innocent girl teased for her name, is kidnapped and finds herself on Mermaid Island. She discovers she has special abilities triggered through physical intimacy.
Mirei, another castaway, becomes her partner, helping Mamori unlock her powers. Together, they must navigate the dangers of the island and learn to control Mamori's transformations.
The island is populated with various factions and individuals, some friendly and some hostile, each with their own agendas. Mamori and Mirei's bond and unique power will be crucial for their survival in this scandalous environment.