Mermaid princess Coral gathers abandoned coins from the pond in hopes of fulfilling her wish—to fall in love as a human. One day, 30-year-old Manato Koganei falls into the water and catches sight of her. Charmed by her beauty, Manato returns to search for her, but unfortunately, he finds her taking her last breath.

The god of the pond suddenly appears, asking Manato for a piece of his life in exchange for saving Coral. After hearing his desire to make her wish come true, Coral comes back to life, transforming into a human the next day. But instead of becoming a woman, she turns into a man!

However, before chasing love, Coral must learn how to live on land. While Manato helps the mermaid live as a human, he cannot help but develop feelings for Coral, regardless of her current form. As they face challenges within society and romance together, their relationship only grows.