For generations, Shintaro and his school of salmon have resided in a small lake. However, their constant struggle for food against larger fish has left them exhausted. Driven by the tales of a vast ocean with an abundance of food, they set out on a daring journey. But, as they follow Shintaro's lead into the sea, they quickly learn the harsh reality of their situation and the perils that await them outside their sheltered lake. This story is comprised of all 16 chapters of "Crimsons Gaiden: River Side Story."