Haruka Nanase, the most beautiful merman in the ocean, had had enough. He'd had enough of being auctioned off to other mermaids to do their handy-work for them. Haruka knew that those jobs he'd 'earned' at the auction were merely attempts at finding Haruka a wife. He hated being set up for dates with mermaids that he'd never even thought of getting with. The truth was that Haruka loved to swim and that's all there was to it. But everybody wanted a piece of him and Haruka had to leave. It was forbidden to go up to the surface, but that might just be Haruka's only hope when it comes to escaping the madness. By reaching the surface, Haruka becomes Haru, and he meets this one firefighter named Makoto Tachibana who just can't help but be drawn in to Haru. And he just doesn't know why.