One day, Kasumi and her husband Satoshi are suddenly held captive by a mysterious man. In the cage are Sagawa, who seems to know something, Machida, who has a fearless smile, and Leiya. The two are shocked for a moment, but then a voice rings out saying, "Now, everyone will have sex..." and the timer begins to count down. Urged by the men around them, Kasumi and Satoshi have sex in public. However, when he has trouble inserting himself in this unusual environment, Sagawa and Machida attack him...