In a world where whale monsters run rampant, humanity's only hope is Fishermen, who possess special abilities to fight them. Iri also dreams of becoming a great hero, but he just has a boring, ordinary life. That is until he runs into a monster one day and realizes he has a mysterious power called Bloodsurge. Now Iri must learn to control it and prove he can be a true Fisherman, despite doubters and enemies growing wilder. Will he succeed, or will the whale monsters prevail once and for all?