Shamoto runs a small tropical fish shop and lives a quiet and simple life.However, this tranquility was broken by the incident where his daughter Mizuko was robbed in the supermarket.Just when she was panicked and embarrassed, a man named Murata came forward to relieve her.He comforted the store manager with a gentle attitude and also comforted Mizuko's panic. Murata himself runs a tropical fish shop, and the life trajectory of Shamoto quietly intersects.The two gradually became familiar with each other, and their friendship seemed to grow slowly through daily conversations and sharing.However, under that kind face, Murata hides unknown secrets - the darkness buried deep in his heart is spreading quietly, bringing a peaceful life into the whirlpool.