The series focused on an American History class at fictional Walt Whitman High School in Los Angeles, though it also covered other events at the school. The class, held in Room 222, was taught by Pete Dixon, an idealistic African-American teacher. Other characters featured in the show were the school's compassionate guidance counselor Liz McIntyre, who was also Pete's lady friend; the dryly humorous school principal, Seymour Kaufman, and fidgety, petite, somewhat spacey Alice Johnson as a young teacher. Also shown was Miss Hogarth as Mr. Kaufman's secretary. In addition, many recurring students were featured from episode to episode.
Pete Dixon was portrayed as idealist and delivered gentle lessons to his students in tolerance and understanding. Students admired his wisdom, insight and easygoing manner. The themes of the episodes were sometimes topical, reflecting the current political climate (the late 1960s and early and mid-1970s such as the Vietnam War, women's rights, race relations and Watergate). However, most plots were timeless and featured themes common to teenagers of any era. For example, the episode entitled, "I Didn't Raise My Girl to Be a Soldier?" (1974), deals with parent-teenager issues and gender role issues.