Time travel stories are often full of crazy variables, paradoxes, and plot holes, which is especially true for The Terminator franchise. From the origins of Skynet to the endless cybernetic showdowns, this is the complicated Terminator franchise explained. Come with us if you want to understand.

In the world of The Terminator, humans create advanced supercomputers that eventually become self-aware enough to realize that they’re being threatened. When scientists realize this computer network has become sentient, they attempt to shut their creation down. Seeing humans as an existential threat, the ultra-smart machines set about systematically wiping them out.

In 1997, the computers take control of the United States’ nuclear arsenal and use it to kill as much of the human population as possible. The few surviving humans build an underground resistance, hiding from weapons and robots built by the intelligent Skynet computer network to hunt down and exterminate them. This resistance is led by one man — John Connor. In the year 2029, he leads the most successful attack on the computers since their first strike, effectively shutting down Skynet by destroying their defense systems in what was once Colorado.

Skynet recognizes that Connor will be the biggest threat to its continued existence post-2029. Much in the same way that it launched the missiles on what came to be known as “Judgment Day” back in ’97, the computer network makes moves to ensure its own survival. It sends a killer cyborg back in time with the mission to kill Connor’s mother before John can be born.