|Assassination of Young Sarah Connor|
Big Bear Lake, California
In an attempt to stop the Resistance from winning, Skynet sent a T-1000 back in time to 1973 to kill a nine-year old Sarah Connor before she could grow up and give birth to Resistance leader John Connor. In response, an unknown party sent back a T-800 known as the Guardian to protect the young Sarah.
While young Sarah was out on the lake in a boat with her father, the T-1000 blew up her parents' cabin, killing her mother. It then made its way into the lake in liquid form and entered the boat in that shape. Sarah thought that it was water and the boat was sinking at first, but her father made her swim to safety while the T-1000 killed him. Sarah ended up under the docks where Guardian had just arrived armed with a rocket launcher and rescued her. The two fled the scene, apparently without destroying the T-1000.
With Sarah's parents dead, Guardian raised her. Guardian trained and protected her for the next ten years and the two made plans for when the first T-800 would arrive in 1984 to kill her. The two also built a rough version of the Time Displacement Equipment to travel forward in time and stop Judgment Day, but needed a Terminator CPU to make it work. As a result of their planning and training, when the T-800 arrived in 1984 to kill Sarah, they were ready and eliminated the T-800 easily. A T-1000 also appeared during this time, likely the same one who tried to kill Sarah in 1973 since they had prepared a trap for it too.