Mihira Sanpei talks with a Tohou accent and is a down-to-earth boy with a cheerful and optimistic personality. However, when it comes to fishing, he becomes very serious and is a youth who enjoys fishing more than anything else. The village where he lives in is a natural environment which provides different kinds of fishing challenges. Despite his lack of experience, Sanpei has a first-rate sense with regards to fishing and decides to maxmise his potential by entering into different fishing contests. As he faces various challenges, he learns to solve difficult problems and learn from his mistakes to the extent that he is able to fish anything out of the waters. Along the way, he encounters all kinds of rivals and companions who increase his experience points and help him in his growth.