Morihito Otogi, a high school student who comes from a lineage of ogres, enjoys a peaceful, ordinary life until his childhood friend, Nico, moves in with him. Nico is a witch-in-training, and chooses Morihito to be her familiar. While Nico is thrilled to be reunited with her old friend and crush, Morihito is tasked with the perilous duty of protecting her from a foreseeable calamity. Between the unpredictable chaos caused by Nico's magic, and the awkwardness of sharing a home, their lives become a whirlwind of supernatural hijinks and threats.