Mitsuki is an exceptionally beautiful and kind-hearted female student with outstanding academic performance, the envy of everyone around. A middle-aged neighbor named Torii, who once worked as a writer but now lives in unemployment and despair, falls for her. One day, he moves into the same building as her. Drawn to her beauty and grace, Torii becomes deeply infatuated regardless of age. Watching her daily life from the shadows becomes his new purpose. However, while her everyday appearance seems that of a pure schoolgirl, in reality, she harbors a depraved, lewd, and tragic side—something that will profoundly shock Torii to his core.