Hikaru, a nurse working the night shift, is subjected to degrading and perverse "experiments" by the sadistic Dr. Hirasaka. The doctor uses Hikaru's younger sister, Ai, who is a patient in the ward, as psychological leverage to further manipulate and humiliate her. Trapped in a cycle of abuse and coercion, Hikaru struggles to maintain her sanity before making a shocking announcement about her future with the cruel physician.
While navigating her relationship with Doctor Hirasaka, Hikaru feels consumed by guilt over her best friend Ai's critical health condition. Driven by Ai's desire to experience womanhood before it's too late, the Doctor introduces a provocative new device to share pleasure between the two friends. Following a medical crisis and a successful recovery, Ai is left with blissful, hazy memories of their shared intimacy.
Dr. Ryuji tests a new pheromone-enhancing drug on his wife, Ren, which triggers intense sexual arousal and unexpected digestive side effects. After a provocative encounter outdoors and a bizarre incident involving their pet fish, Ryuji leaves for a medical conference. Ren spends his absence longing for him with a custom toy, only to welcome him home with an eagerness to continue their erotic experiments.