《终结者2：审判日》发生的27年后，由于未来天网派来T-800成功杀死年幼的约翰，以致令未来产生变化，一个全新进化的液态金属终结者从未来派出，目的是追杀持有关键讯息的丹妮·拉莫斯、半生化人葛蕾丝和她的朋友。这使莎拉·康纳以及成功杀死约翰的T800终结者前来帮助她们一行人，以共同为了人类的未来而战。More than two decades have passed since Sarah Connor prevented Judgment Day, changed the future, and re-wrote the fate of the human race. Dani Ramos (Natalia Reyes) is living a simple life in Mexico City with her brother (Diego Boneta) and father when a highly advanced and deadly new Terminator - a Rev-9 (Gabriel Luna) - travels back through time to hunt and kill her. Dani's survival depends on her joining forces with two warriors: Grace (Mackenzie Davis), an enhanced super-soldier from the future, and a battle-hardened Sarah Connor (Linda Hamilton). As the Rev-9 ruthlessly destroys everything and everyone in its path on the hunt for Dani, the three are led to a T-800 (Arnold Schwarzenegger) from Sarah's past that may be their last best hope.