Prep school student Yuichi Mamiya’s father remarried suddenly! New family be 3 people… mother Mifuyu who shoots mature adult charm, eldest daughter gal Natsuki of the huge breasts, second daughter quiet Akiba of the huge breasts. The sexual desire for such mother and daughters is not controlled… A certain day, yuichi obtains a mysterious penlite that does the partner in the hypnotic state only by showing that light! Mother-in-law Mifuyu is first done as the subject of penlite experiment, an indecent act that cannot be normal is done. And sister-in-law Natsuki and Akiba, that body is opened for Yuichi by the hypnotic effect.