Planet of the Apes - the series - featured the continuing adventures of human astronauts Alan Virdon (Ron Harper) and Pete Burke (Jim Naughton), in the far-flung year of 3085 (starting March 21, 3085, if we're to believe the spaceship chronometer...) on a world run by intelligent, talking simians.
In "Escape from Tomorrow," the introductory episode written by Art Wallace and directed by Don Weis, we begin with an old man (in a bad wig) being pursued by a child chimpanzee and his pet dog in a rural setting.
My first thought watching this sequence was that it was a canon violation (alert! alert!), since Conquest of the Planet of the Apes had established that a space plague had arrived on Earth in the late 20th century and killed off all the cats and dogs. It was the death of "beloved pets," in fact, that led humans to enslave apes...which would then lead to the uprising of the gorillas, chimpanzees and orangutans. This fact seems like something that the producers of the series should have taken care to remember, since it is a lynch pin of apes continuity. On the other hand, this sequence occurs a thousand years after the plague, so I suppose it is possible that "life has found a way," (to quote the Jurassic Park films), and dogs have re-entered the chain of life on Earth.
After the Old Man presents the astronauts with a book of pictures from New York City in the year 2505 (another troublesome continuity point that contradicts the movies...), the astronauts realized that they have returned home indeed. That the planet of the apes...is Earth.
"Another ship, Zaius," states Urko, "it's hard to believe." One can imagine that had the series lasted, viewers would have heard much more about these other astronauts and their (apparently-not-very-pleasant...) adventures on the planet of the apes. If that had been the case, the series would have been all the stronger for it.
And yet, I remember this series with tremendous fondness and affection because it had a great deal of value in terms of depicting a society separated by class and race. By putting white humans in the inferior position, the series makes quite a few trenchant points. Ultimately, that's the purpose of good science fiction....to comment on society, and here the set-up is nearly Swiftian. On top of these elements, the series features good actors and a modestly well-drawn future world, thanks in part to the costumes left over from the feature films and the occasional use of stock footage (for Ape City exteriors, for instance).