After a chance encounter with a self-proclaimed kaiju tamer, a high school student is drawn into a world of fighting mechas and monsters.

Yomogi Asanaka is just an ordinary high school boy when he encounters a young man named Gauma, who claims he is a "Kaiju User". When the city is attacked by a kaiju, Gauma summons the giant robot Dynazenon to battle it. Yomogi, his classmate Yume Minami, and local NEET Koyomi Yamanaka are caught up in the battle and end up becoming Gauma's copilots for Dynazenon. Together, they must uncover and put a stop to whatever is behind the kaiju attacks.