Nagasumi’s in hot water after a beautiful, young mermaid named Sun saves him from drowning. The deep-sea sweetheart’s dad is a merman Yakuza prone to executing anyone who learns his family’s scaly secret! Luckily, there’s a catch – if Nagasumi agrees to marry Sun, he just might avoid sleeping with the fishes!

Of course, the honeymoon ends before it even begins when Nagasumi finds his life flooded with gilled gangsters looking out for their boss’s little girl. The kid’s definitely in over his head, but there’s no denying the mermaid’s allure – Nagasumi’s hooked and Sun’s ready to come ashore!