College student Hayashi is suddenly struck by severe abdominal pain, writhing in agony on the street. He's rescued by pharmacist Yuu, who prescribes him a special medication. However, the medicine turns out to be an unexpected erection-enhancing drug. Although Hayashi manages to relieve his pain, he's now plagued by an endless surge of intense desire. Unable to endure it any longer, he seeks help from Yuu—but when he stands before her, his fully erect, throbbing cock is impossible to hide. Seeing his state, Yuu approaches Hayashi with an incredibly seductive smile…