1984
A T-800 Terminator is sent back in time to kill Sarah Conner before she can give birthd to John Connor, the leader of the resistance fighters trying to destroy Skynet. Kyle Reese is also sent back in time though instead of killing Sarah it is his mission to protect her at all costs. A brief affair ended up having the result of Sarah falling pregnant with the child that would grow up to be John Connor...

1995
Skynet sends a re-programmed T-800 back in time once more, but this time his mission is to take out a ten year old John Connor, who until he met a T-1000 Terminator sent to protect him didn't believe the stories his mother told him of a nuclear war that would wipe out the human race and leave him in charge of their survival. With the help of the T-1000 Terminator John breaks his Mother out of Pescadero State Hospital and the three of them team up with Miles Dyson - a man whose research would lead to Skynet's creation - to destroy all of Cyberdynes research. They think that they've wiped out all traces of Skynet and stopped Judgement Day, but this turns out not to be the case...

1999 - 2007
John and Sarah are on the run from the authorities in regards to having destroyed the Skynet research and for the supposed murder of Miles Dyson. A Terminator is sent from the future to finish John off once and for all, but another, Cameron, has been sent to protect him. She takes them forward in time to 2007, four years before the destruction of the world and the start of the Skynet production.

Cromartie's mission was simple enough. Kill John Connor and instantly wipe out the Resistance against Skynet after Judgement Day. In theory this should have been easy enough, but when its target had the help of another Terminator, Cameron, and the support of his mother, Cromartie was forced to learn for itself that the only way to John Connor was to take out one of them. He chose the easiest option and the one that would put up the least resistance against him and kidnapped Sarah Connor. Despite all attempts to get her back, John and Cameron were forced to resign themselves to the fact that they weren't going to see her again.