A decade has passed since sea creatures gained the power to morph into behemoths, unleashing terror upon the city. Average highschooler, Natsuzo Umitsuki, becomes embroiled in one of these catastrophic events, his fear paralyzing him with the belief the city is doomed. Until a girl wearing shark-shaped hand puppets charges to his aid - Ichika "Shark Girl" Fukada - utilizing her "Shark Punch" move to save Natsuzo and the town's inhabitants.
To Natsuzo's surprise, Ichika transfers into his class, but despite her heroic intervention, he discovers she's timid, clumsy, and petrified of the colossal sea beasts. Ichika's courage sparks something within Natsuzo, spurring him to become stronger and protect Ichika.
As their vibrant days unfold, Natsuzo and Ichika become closer, but the marine monsters continue to threaten the safety of their carefree lives.
