My name is Mukai, Jibun. Recently, mail-order parcels have begun to arrive at my home. Almost all of the addresses are mail-order packages addressed to my sister Ai. One day, thinking that it was too much, Jibun, as an older brother, went to the room to pay attention to his sister. Then, there, my cute little sister was masturbating alone with Aheahe while being surrounded by a thick domaso toy that was far from her innocent appearance ...!