Kei Kusanagi isn't your typical 15 year old high school student. He's actually an 18 year old with a rare disorder that puts him into what he calls, a "standstill". When he was younger, this disorder left him in a deep coma which stunted his growth for the next three years! Mizuho Kazami isn't your typical teacher either. She's actually an alien sent by the Galaxy Federation to observe the Earth! As the sole human being with knowledge of Ms. Kazumi's secret, Kei must...marry the alien?! Homework, dating, and a gorgeous wife -- going to school has never been quite this fun!