Morihito Otogi, a high school student who comes from an ogre lineage, enjoys a quiet, ordinary life until his childhood friend Nico moves in with him. Nico is a witch-in-training and chooses Morihito as her familiar. While Nico is excited to reunite with her old friend and in love, Morihito is tasked with the dangerous duty of protecting her from a predicted disaster. Between the unpredictable chaos caused by Nico's magic and the inconvenience of sharing a home, their lives become a whirlwind of supernatural intrigue and threats.