The Terminator
A cyborg is sent back in time, by the sinister computer network Skynet, to murder a woman who will one day give birth to the leader of the militia destined to end the coming robo-apocalypse.

Terminator 2, Judgement Day
The cyborg who once tried to kill Sarah Connor is dead, and another T-101 must now protect her teenage son, John Connor, from an even more powerful and advanced Terminator, the T-1000.

Terminator 3, Rise of the Machines
John Connor is now in his 20's, and a female terminator, called T-X or Terminatrix, is after him. Another T-101 is sent back through time to protect John once again on the verge of the rise of the machines.

Terminator Salvation
After Skynet has destroyed much of humanity in a nuclear holocaust, a group of survivors led by John Connor struggles to keep the machines from finishing the job.