In Episode 1 of Kyonyuu Daikazoku Saimin (also known as Big Big Family Hypnosis), the story introduces Yuuichi Mamiya, a young man who receives a mysterious penlight with hypnotic powers. Using this device, Yuuichi begins to manipulate the women in his household, including his stepmother Mifuyu and her two daughters, Natsuki and Akiha. The penlight allows him to fulfill his desires by placing the women under his control, though it cannot force them to do anything against their will.
The episode explores Yuuichi's gradual escalation of control, starting with seemingly innocent commands to "get along as a family" and progressing to more explicit and intimate interactions. The women, initially unaware of the hypnosis, begin to act on their suppressed desires, leading to a series of erotic and taboo encounters. Yuuichi's ultimate goal is to create a "real family" by impregnating the women, further deepening the moral ambiguity of his actions .
