Mark Thackeray (Sidney Poitier) is an engineer who loses his job and turns to teaching in a tough East End school. He immediately faces hostility from his students - the graduating class - who are determined to break his spirit. However, Thackeray counters by treating the teenagers as young adults, attempting to prepare them for life in the outside world. Gradually, as he takes the class on field trips to museums and similar outings, Thackeray earns both their affection and respect.