The Sket-dan get a new assistant homeroom teacher (who wants everyone to call her, Onee-san), but she's a klutz and is upset she can't be a good role model for the students, so the Sket-dan ask Chuu-san to help with some of his strange drugs. Later, Switch goes through some old inventions of his that didn't work out as intended...
And so, a new character, 
Onee-san-sensei, was added,
Y de esta forma conocemos a Oneesan 
sensei, un nuevo personaje
Y de esta forma conocemos a Onee-san 
sensei, un nuevo personaje
E assim, a nova personagem, 
a professora Maninha, entrou