Rimuru becomes the new teacher for Shizu's students. However, having been summoned into this world against their will and facing shortened lifespans as a result, the children's feelings are complicated, and they're reluctant to accept Rimuru. So Rimuru proposes a series of mock battles with each of them to ascertain their abilities and allow them to let off steam.

In the heart of the labyrinth, Shizu's students pray to summon superior spirits. As Rimuru watches over, an overwhelming presence appears. Will Rimuru finally be able to fulfill his promise to Shizu?