Kohaku Natsuno appears to be an ordinary female student, but in reality, she is an undercover investigator for a secret organization, operating under the codename "Izu Kohaku." Today, she infiltrated an enemy hideout with her colleague Yano to conduct an investigation, but they were captured and subjected to intense interrogation. Following orders from their boss, Yano appears as the interrogator and begins questioning Kohaku. She remains completely silent, but Yano forcefully breaks her resistance by applying direct physical stimulation to her body. The torture involves pain and discomfort, yet Kohaku proves highly sensitive to sexual stimulation, reacting involuntarily despite herself. Bound to a bed, suspended in a dungeon, and repeatedly creampie-fucked—humiliated and tormented in degrading positions—Kohaku's expression gradually reveals a strange bliss and pleasure. Her reactions expose her weakness: while trained to endure conventional torture, she is vulnerable to pure sexual stimulation.