At the start of the series, after her first day at her new school, Mahiro goes to check on her brother Kazuki who has been ordered by Mita, a school professor, to serve an after-school punishment. She soon runs into Kazuki who is fleeing from Mita, who has revealed himself to be a man-eating homunculus. Kazuki tells Mahiro to run away, but, not understanding the situation, she remains still. Mahiro is then surrounded by the jaws of Mita as he emerges from the ground, and she is swallowed whole.
In the manga, Mahiro is rescued by Kazuki who, after activating his alchemical powers, is also swallowed, but bursts free from Mita with a giant lance with Mahiro in his hims. In the anime, Mahiro is rescued by Tokiko Tsumura who arrives on the scene and easily destroys Mita.