Kawaki goes to the Ninja Academy! Undercover on a mission to protect a princess, he enrolls at the Academy along with Himawari. Although Kawaki struggles with academy life, he manages to befriend his watch, Princess Kae. But suddenly kidnappers run off with Himawari! Later, Kawaki's true identity is almost uncovered during the rehearsal for a play about the Legendary Sannin. Things go from bad to worse when Kae is kidnapped as well and Kawaki comes face-to-face with a dangerous assassin!