Kei Kusanagi is sitting on a grassy field one night when suddenly an alien ship appears and he is chased by what he believe to be an alien. The next day at school as Kei decides on whether what he saw was real or not, he is informed that his class's old teacher suddenly quit and will be replaced by a young, gorgeous teacher. Much to his suprise, the "teacher" is none other than Mizuho Kazami, the "alien" he had seen the night before. When discussing what happened in a school utility closet the two are discovered and thought to be having an elicit affair. Kei puts out the idea that the two are married and suddenly, his life changes in an instant. Will Kei and Mizuho be able to keep the secret that she's an alien from the rest of the school? Will their relationship actually work out?<br />