In the classroom after school, Yuta Hibiki draws and erases Gridman in his notebook over and over again. Once upon a time, this world was created and destroyed by a single girl. The ones who saved the girl's heart were Hyper Agent Gridman, who came from another dimension, a monster with a heart she created, and Yuta and the others.
Yuta, who is now a sophomore in a different class from his friend Rikka Takarada, decides to confess. Their daily life in such a peaceful world began to crumble with a roar.
In the midst of Yuta's crisis, Gridman suddenly reappears and says,
"The balance of this world is about to collapse."
Before long, the crimson dragon "Dynarex," Gridman's collaborators, the Neon Genesis Junior High Students, and Yomogi Asanaka, a resident of another world, appear in front of Yuta one after another.
While hiding his feelings for Rikka, Yuta's extraordinary life begins.
