Hammer Mermaid!
From Prozess: Okad Kayichi almost drowned in childhood, leaving him with injury from water. Now it falls into fainting at the slightest contact with water. By his regret, his girlfriend takes him to the pool to charm his swimsuit. By chance, Keiichi falls into the pool and saved by a swimming instructor, Mizushima. Cayichi feels something special in it, and even Mizusima seems to know something about the past Cayichi. What will happen to Caiti now?