Skynet discovered that the timeline between humanity and the uprising of machines is unbalanced. It created a robot called T-Infinity. The new robot is intended to correct the unbalanced timeline.
In the year 2033, Skynet is infiltrated by the Human Resistance. The core is still intact. Skynet's main system notices the unbalanced timeline between past and present. The Resistance discovers the same problem during a simulation. Skynet develops a prototype of a robot known as the T-Infinity. Skynet then uses advanced technology to send the T-Infinity into the past. The robot is programmed to correct the balance.
The T-Infinity arrives in the past on July 17, 2009. John Connor leaves Crystal Peak Mountain after the death of Kate Brewster. Mankind is destroyed while Skynet is victorious. John goes to post-apocalyptic Los Angeles to meet with the Human Resistance. He is attacked by Terminators during his journey. A man called Uncle Bob saves John. Uncle Bob reveals himself to be a Terminator who was sent back in time. The Terminator's objective is to help John become the leader of the Human Resistance which is still his destiny. Eventually, John and Uncle Bob meet the Human Resistance at an abandoned subway in Los Angeles. Suddenly, the T-Infinity appears and begins attacks members of the Resistance. Uncle Bob fights the T-Infinity to protect John. Uncle Bob uses a plasma rifle to destroy a building located above the T-Infinity. John and Uncle Bob escape.
The T-Infinity manages to survive the wreckage and hides someplace that is discrete. John, Uncle Bob, and the Human Resistance find an abandoned radio station. They use it to contact other humans. They send a signal which is intercepted by Marine sergeant Tara Holden. He is accompanied by a group of other soldiers. They meet John and the Human Resistance at the radio station. The combined forces penetrate a weapons factory. They are confronted by the T-Infinity upon entry. It manages to defeat Uncle Bob in a fight. After Uncle Bob is defeated, the T-Infinity leaves without fighting John. An alarm starts which draws the attentions of several robot tanks. John, Holden, and the other soldiers manage to escape in a hijacked machine. Meanwhile, Skynet still believes that other targets are responsible for the unbalanced timelines. The T-Infinity is recalled to 2033 and sent back into the past.
The T-Infinity arrives in 2015. Its current assignment is to kill Tara Connor. The T-Infinity attempts to raid the Resistance's headquarters, but it is temporarily disabled by an electromagnetic pulse. John Connor attempts to use a steel bar, but it causes the T-Infinity's on-board equipment to malfunction. As a result, the T-Infinity is sent further back in time.
The T-Infinity arrives in Birmingham, Alabama during 1996. Its system is misdirected by the malfunction. Sarah Connor becomes a top priority instead of John Connor as originally intended. The machine goes to young John Connor's school. It kills the principal before Sarah's arrival. The T-Infinity fails to terminate Sarah during their first encounter. She runs through a nearby street but is pursued by the machine. The T-Infinity follows her to the Connors' hideout in the woods. The Sarah and the other Connors battle the T-Infinity. Young John Connor uses a bazooka to destroy the T-Infinity's right arm. The rest of the T-Infinity is destroyed when it is attacked by a wolf.