High school student Kei Kusanagi is in an unusual situation. Not only is he an 18 year-old in a 15 year-old's body because of rare disorder that put him in a coma for three years, but he has also found out that his incredibly attractive teacher is also an alien. Now, the alien race that sent Kei's teacher to Earth is forcing him to marry her, a situation to which Kei is not opposed. Now, however, he must keep her secret, do his homework, and be a good husband