ONE

Naofumi Iwatani is an otaku and shy boy who gets summoned to a magical realm where a series of "waves" of monsters is destroying its population. He is supposed to fight against them with the help of a magical shield and with four more heores but after a princess accuses him, falsely, of having raped her he is treated as an outcast, neverthless, he will find unexpected allies through his path and he will finally become a hardened warrior.

Human civilization is split between two races, one living on the surface and one living on the ocean floor. After their school closes down, four students from the sea village, Shioshishio, have to attend school on the surface. This series explores the troubled relationship between the sea and land people, and the feelings of the younger generation as they struggle to find their place in the world.