Mitsuru lives as a freeloader at his aunt Yumi's house while attending university. However, his dim hopes crumble the moment he steals a peek at his girlfriend's aunt's diary. What she wrote was that she had a single-minded love for the man she loved, and as proof of that, she shaved her head. What's more, even after the man leaves, she keeps shaving and masturbates every night to increase her feelings for him. He feels angry that he cannot fill the void in Yumi's heart.