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.