Unman, Wittering and Zigo (1971)

Fed up with the frantic advertising world, former marketing executive John Ebony takes up a position as a teacher at Chantry, a public boarding school for boys. Eager to fill in for his unfortunate predecessor and educate the next generation of pupils, the unsuspecting first-time instructor is shocked to discover that his efforts to exercise authority have the exact opposite effect of what was intended. Then, the seemingly respectful but devilishly manipulative teenagers of Class Lower 5B drop a bombshell, and Ebony starts fearing for his life. After all, it is evident that the unruly students have the upper hand. And as if that weren't enough, Ebony has to deal with a pompous headmaster and a sceptical wife. But now, there is no turning back. What happens if John fails to cooperate? Can he cope--and survive?