The terminator is a very successful science fiction movie franchise. It is about a post apocalyptic future where humans are fighting the machines. John Connor is the one who leads the humans in the war against the machines.
The Machines become self-aware and take over earth. Humans put up a resistance. John Connor’s mother, Sarah Connor, is central to the movie’s theme. Before this happens Sarah Connor is put in a lunatic asylum because no one believes her story.
The machines devise a way of trying to kill Sarah Connor in T1 and then John Connor in T2, by sending killer cyborgs back in time. In T2 John Connor sends a cyborg back in time himself to protect his young self from the cyborg sent by machines. The young John Connor teams up with this T-800 cyborg to rescue his mother from the lunatic asylum and defeat the T-1000.
In T3 the story moves on and a similar attempt is made by the machines as in T2. It is countered by John Connor in a similar fashion by sending T-800 101 to protect himself. The movie ends with John Connor and his girlfriend finding refuge in a nuclear bunker, and the machines become self-aware and launch nuclear weapons.
The next movie in the franchise shows a post apocalyptic dystopian future destroyed by nuclear bombs. The machines hunt and capture humans and put them in prisons. John Connor leads the resistance and the battle between humans and machines rages on.