When high-school freshman Yomogi Asanaka stumbles across kaiju user Gauma, he and a few unsuspecting onlookers get caught up in a fight against kaiju.

One of the Kaiju Eugenicists, Juuga, tells Yomogi that they were betrayed by Gauma. Yomogi and the others become distrustful of Gauma but they end up having to fight a Kaiju with their hearts in disarray. With their hearts separated, Dynazenon is unable to unleash its full power.

Yomogi catches a cold and goes to sleep. Gauma gets Yume to visit him. Yomogi is confused by Yume's sudden visit, but the relationship between the two slightly unravels. When Yume hears that a monster had appeared, she leaves Yomogi with his cold and heads for battle.

Dynazenon is defeated by the Kaiju. A mysterious giant that appears. Despite the confusion, Onija and Mujina begin to fight the giant. Gauma has no way to repair the damaged Dynazenon.

Yomogi and Yume hear about how Kano died. A Kaiju suddenly appears without them being able to take in the story. Meanwhile, Chise holds onto a secret.

Yomogi and the others combine into Dynazenon once more for the final battle.