Shuriken School - Season 1 Episode 9 Kubo's Mystery

Kubo has been so terribly boring lately that no one can listen to his classes. If this continues, the kids will end up a year behind. Our three heroes decide to intervene. They want to find out WHY Kubo is so deadly boring. They follow him, and learn that Kubo not only has a very boring life, but that he mutters the same name in his sleep every night - 'Torofi'. They set off to discover the identity of this mysterious Torofi, travelling back into Kubo's past. They learn about an old feud between Kubo and his sister.