Terminator Salvation also referred to as simply Terminator 4, T4 or TS is a 2009 American science fiction action film directed by McG and starring Christian Bale and Sam Worthington. It is the fourth installment of the Terminator film series. In a departure from the previous installments, which were set between 1984 and 2004 and used time travel as a key plot element, Salvation is a postapocalyptic film set in the year 2018 and focuses on the war between Skynet machines and humanity, with the human Resistance fighting against Skynets killing machines. Bale portrays John Connor, Resistance fighter and central character to the franchise, while Worthington portrays cyborg Marcus Wright. Terminator Salvation also featured Anton Yelchin as a young Kyle Reese, a character first introduced in The Terminator, and the film depicts the origin of the T800 Model 101 Terminator.
In 2003, Dr. Serena Kogan Helena Bonham Carter of Cyberdyne Systems convinces death row inmate Marcus Wright Sam Worthington to sign over his body for medical research following his execution. One year later, the automated Skynet system is activated, begins to perceive humans as a threat, and eradicates much of humanity with nuclear weapons in the event known as Judgment Day.In 2018, John Connor Christian Bale, leads an attack on a Skynet base, where he discovers human prisoners and schematics for a new type of Terminator, incorporating living tissue. He is the only survivor of the assault after the base is destroyed in a nuclear explosion. Following Connors departure, Marcus emerges from the bases wreckage and begins walking towards Los Angeles. ........
Source: Wikipedia