Chiba Erika, the second daughter of the Chiba family. A competitive kendo player, she rashly makes a promise to a delinquent member of the kendo club to "do whatever he says if he loses" in order to reform him. However, she is defeated by her opponent's hidden skills and is forced to offer herself to the dojo.
"This kind of thing in the dojo... I won't allow it!"
On the sacred tatami mat, her brave body is played with by a man, and a milky white liquid overflows from her lower body, wetting her kendo uniform and dripping onto the floor. The scene spreads miserably across the ground, symbolizing her future. The man photographs her blunder and uses it as blackmail material.
From then on, Erika becomes a convenient tool, servicing his penis whenever he calls, in the school bathroom or on the rooftop. Though she endures the humiliation, repeated sexual intercourse builds a memory of pleasure in her body, gradually corroding her mind.
A few months later, Erika is completely changed. Her stern expression vanished, and she transformed into a lustful bitch, wearing heavy makeup and revealing prostitute clothing, seducing men. In the dojo, classrooms, and schoolyards, she was everywhere in the school, smiling with joy and enjoying the pleasure of sex with all her heart and soul.