Pete Dixon's class is studying civil disobedience apostle Henry David Thoreau, and Pete mentions that the city is planning to cut down the trees along his street to widen it for better traffic circulation. His class is inspired to show up there to stage a protest against the removal of the trees. The ringleader is Grady Garrett, an impressionable young student who already clashes frequently with his father, a doctor who is distressed that Grady doesn't want to follow him into the profession. Grady's father decides that the cause of Grady's new-found rebelliousness is Pete Dixon, whom he wants removed as a teacher.
—aldanoli