Aoi, a female doctor who is a surgeon at a private hospital in Tokyo. She is made a subject of a human experiment because she rejected Sadamatsu, a colleague doctor who seeks physical relationships with evil emotions. What is the secret experiment conducted in the hospital? "The uterine ostium where women can get the most pleasure, so-called Portio, is approached with medication and electric current." Aching sensation awakens from the deepest part of the uterus ... The woman becomes captivated by the Portio sensation.