Sayoko Saeki

Sayoko Saeki, or Sayoko-sensei, is presented as a temporarily new teacher and counselor at the Mikami College in Japan, but in reality she is an undercover agent who works for a secret organization that's trying to investigate on strange drug affair in the institute. However this is not her only secret, in fact she, her chief, the principal of the school and many other students are hidding a much more lustful mystery. Furthermore she looks a lot like a bustier version of the deceased mother of Junichi Yano, one of the students, who is perhaps the only harmless, innocent and unaware person in the entire school.