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...
If you'd like, please have 
some of Onee-san's rice...
Si desean les puedo dar algo 
del arroz de Oneesan...
Si queréis puedo daros algo 
del arroz de Onee-san...
Se vocês quiserem, 
peguem o arroz da Maninha...