Ninja Hattori-kun

Kenichi Mitsuba is an ordinary schoolboy whose life changes when Hattori Kanzo, a young ninja from the Iga mountains, comes to stay with his family. Hattori attends school in secret while using his ninjutsu to help Kenichi through problems that would normally be far beyond him.

Hattori is soon joined by his younger brother Shinzo and the ninja dog Shishimaru, making the Mitsuba household even livelier. Their greatest nuisance is Kemumaki, a rival Koga ninja who hides behind the image of a model student and schemes with his cat Kagechiyo to outwit Hattori and embarrass Kenichi.