Fei, the second prince of the country Touya, is in the middle of a violent dispute over the inheritance of the royal throne. Fumihiko, the director of Fei's school, has assigned Teien to protect Fei from any assassins sent by the opposing faction. But Fei doesn't trust Teien, and to make matters worse, just as Fei is about to ask that Teien be replaced, Teien accidentally finds out Fei's secret and...??