The story revolves around a highschool boy named Niwa Makoto. He lives with his aunts family since his parents are away on business. It is there where he meets his mysterious cousin of the same age Touwa Erio who happens to tie a futon mattress around her upper body and is a self-proclaimed alien. Her staple food is pizza. Erio had been missing for half a year and was found floating in the sea. She doesn't remember anything about what happened during that period of time, but she began to think that it was the act of an alien and wanders the neighbourhood wrapped in the futon.
Eriko and her friends Yuma and Ayano are excited about entering high school. Their excitement leads to their breaking of the rules when they toured the school before the opening ceremony. They find out their preconceptions about the all female school may not be as true as they had first thought. Despite that, Eriko and her friends are joined by new friends. They aim to get through high school life together. (Source: ANN)