One day, Hijikata, Gintoki, and Yamazaki each received a letter. It told them to come to a 'certain place.' After arriving and waiting, they were all hit on the back of the head in a ridiculously pathetic and sudden way... and ended up trapped. They are in a white room with absolutely nothing in it. It's exactly like one of those 'Room You Can't Leave Until You Have Sex.' Just as they think that, they see 'Sex Room' written on what looks like a door. What on earth is going to happen?