Miss Mizuho Kazami is no ordinary high school teacher. She is actually a resident observer for the Galaxy Federation. Right after she lands on Earth, Kei Kusanagi sees her materialize. The next morning by the lake, he discovers that she is his homeroom teacher, and his neighbor. After getting caught alone in the supply room at school late one night by Kei's uncle, aunt, and the principal of the school, Kei's uncle announces that the two were secretly married. Then Kei reveals he is actually 18 years old instead of 15.
Mizuho has many different personalities. Though she is 23, and her father was human, she knows little to nothing about Earth except a love of the best candy in Japan. She has two living relatives, her mother and sister. Her sister, Maho, threatens Kei every time she sees him, and more than once tried to kill him. Mizuho's mother, Hatsuho tries to show Mizuho many sexual tricks.
