Season 3 of the original series concludes with Donald Pleasance as a college professor forced into retirement, whereupon he questions whether he has accomplished anything of substance and contemplates suicide. Dark! But don't worry, it gets better ...

The Twilight Zone, Episode #102: "The Changing of the Guard" (original air date June 1, 1962)

The Plot: Professor Fowler (Donald Pleasance) has been teaching poetry to young men for 51 years. As he recites a poem, however, he looks around the classroom at his students. Most of them are not paying attention and some look outright bored. At the conclusion of the class, he informs them that's he's never "encountered such a class of dunderheads," though he adds with affection: "But nice dunderheads."

As he tells the school's headmaster, he shall be content to continue teaching until the end of his life. The headmaster, however, informs him that it's time for a younger man to take over the class; Professor Fowler is urged to accept an offer of retirement, which catches him by surprise.

Returning home, Professor Fowler is clearly unsettled by the news, and falls into a pensive mood that drops directly into despair and depression. 'What good did I accomplish?' he wonders. All he did was teach the same thing year after year; he himself never did anything, he concludes. He removes a revolver from his desk drawer and walks outside, into the cold of a late December evening.

On the verge of shooting himself through the head, Professor Fowler hears bells ringing at the school. He investigates and ends up in his classroom, where he is presented, let us say, with a very different view of what he has truly accomplished over the years.

The Goods: What a lovely, elegaic conclusion to the season! Even though it must have seemed odd to have a Christmas-themed episode airing in June, the sentiment and the emotions certainly ring true.

The episode, written by Rod Serling, serves as a tribute to educators, who are among the most valuable and least appreciated people on Earth. Though it's set at a fictional college, the statue where Professor Fowler contemplates commiting suicide is of Horace Mann, the first president of Antioch College, Serling's alma mater, and features a quote by Mann: "Be ashamed to die until you have won some victory for humanity."

Pleasance brings it all home. Though only 42 years of age, he plays the much older Professor Fowler -- who had to be in his 70s or older -- with grace and conviction. The episode may be sentimental, but it's earned and doesn't overindulge in the emotion, which makes it all the more effective.

The Trivia: This was the first appearance by Pleasance on American TV. He had a memorable supporting part as a nearly-blind chap in The Great Escape the following year and played the villainous Blofeld in the James Bond adventure You Only Live Twice five years later, among many other roles. His most iconic role is probably his turn as Dr. Sam Loomis in Halloween.

After the season ended and the show was cancelled, Serling accepted a teaching post at Antioch College for the 1962-63 school year, covering classes on writing, drama, and the media. During that time, he also worked on the screenplay for the political thriller Seven Days in May.

On the Next Episode: The original series was cancelled after three seasons, but brought back as a mid-season replacement, with episodes lengthened to a full hour. Season 4 begins with a young man's urge to kill, amidst concerns about his true origin. And if I can find a home video version within the next 24 hours or so, our coverage will continue tomorrow!

Catching up: Episodes covered by Twitch | Episodes covered by Film School Rejects

We're running through all 156 of the original Twilight Zone episodes, and we're not doing it alone! Our friends at Film School Rejects have entered the Zone as well, only on alternating weeks. So definitely tune in over at FSR and feel free to also follow along on Twitter accounts @twitchfilm and @rejectnation.