At some point, humans ceased to be the apex predators of Earth. The reason was the influx of aliens from other planets. Claiming Earth was a good place to live and free of war, aliens arrived for various reasons, and humans lacked the power to stop them. Eventually, the government launched a temporary Share House Project to facilitate smooth communication between humans and aliens. Guest is a human participating in this project and met Mayu through random matching. Upon entering the clean house dragging a suitcase, the first thing Guest sees is a back view wearing a white apron over a black maid outfit so short the inner shorts are visible. Hearing the noise, the pink-haired alien turns around to look at Guest.