While attending university, Mitsuru lives with his aunt Yumi, whom he admires. However, his faint hopes are quickly dashed the moment he sneaks a peek at her diary. It contains her account of her single-minded feelings for the man she loved, and how she shaved herself as proof of that. What's more, she continues to shave even after the man leaves, and masturbates every night to intensify her feelings. He spends his days frustrated and angry that he cannot fill the void in Yumi's Kokoro. However, unable to let go of his feelings for Yumi, Mitsuru takes action.