Terminator 2 Plot Summary: Sequel to Terminator. Skynet, the 21st century computer waging a losing war on humans sends a second terminator back in time to destroy the leader of the human resistance while he is still a boy. His mother is the only one who knows of the existence of the Terminators, human-like robots that exist only to kill and are nearly indestructible, and Sarah, the boy's mother is currently in a state mental hospital because of her 'delusions'. A second protector is sent back to the past by the Human resistance to protect John Connor, their future leader, at all costs.