The terminator is back, this time as a "good guy", to protect the young John Connor from the evil cyborg, the T-1000. Both units arrive back from the future and both are looking for John, now a troubled teen being raised by foster parents. John's real mother, Sarah Connor, has been placed in a psychiatric hospital for her insistence in an impending ‘Judgment Day', a nuclear holocaust that will annihilate billions of people, as well as for her belief in the first terminator unit, which attempted and failed, to kill her. The T-1000 is a more advanced machine than the older terminator unit. Besides being virtually indestructible, it's capable of morphing into any shape, including a human. Sarah knows that "Judgment Day" is coming soon and must escape to save her son and stop the nuclear disaster. At Cyberdyne, the research company where the first terminator's CPU are being kept, Sarah explains to Miles Dyson that they must destroy it to keep "Judgment Day" from occurring and that the fate of humanity is clearly at stake. Cyberdyne's research on the first terminator's CPU led to the development of an unstoppable artificial intelligence network called Skynet, which would be responsible for the nuclear holocaust to come.