Desc: Perry Mason: The Case of the Lethal Lesson: Directed by Christian I. Nyby II. With Raymond Burr, Barbara Hale, Alexandra Paul, William R. Moses. Ken Malansky is a student taught by Perry. Ken hears his girlfriend was assaulted by another student so he confronts him but finds him dead, the weapon his own knife. Perry is slow to take the case as the victim is a close friend's son.