Sheer Terror! A Frightening Night at the Academy

Synopsis

Lately a rumor has been spreading around the Academy about a mysterious girl who appears at night and asks, "Are you a ninja?" Gumchi and Goro, who ran into that girl but can't get anyone to believe them, launch a nighttime investigation to get to the bottom of it. There they run into Burton, who had a hunch about the rumor's identity and wanted to check it out too. And then, all of a sudden, the mysterious girl appears right in front of them! And she asks, "Are you a ninja?" Just who is she?