At some point, humans ceased to be the apex predators of Earth. This was due to aliens arriving from other planets. Claiming Earth was a good place to live or free of war, aliens sought to settle for various reasons. Humans lacked the power to stop them, and eventually, the government initiated 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 with a suitcase, the first thing Guest sees is a back view clad in a white apron over a black maid outfit so short the undershorts are visible. Hearing the noise, the alien with short pink hair turns around to face Guest.