Morihito Otogi, a high school student who comes from a lineage of ogre, enjoys a quiet, ordinary life until his childhood friend, Nico, moves in with him. Nico is a witch in training and chooses Morihito to be her acquaintance. While Nico is thrilled to be reunited with her old friend and lover, Morihito is tasked with the dangerous duty of protecting her from a predicted calamity. Between the unpredictable chaos caused by Nico's magic and the awkwardness of sharing a home, their lives become a whirlwind of supernatural threats and menaces.