Terminator: The Sarah Connor Chronicles is a television series set after Terminator 2: Judgement Day in an alternate timeline that diverges from Terminator 3 and Terminator: Salvation while retaining plot points and elements from those films. Set in the year 2007, Sarah Connor and her son John, the future leader of the human resistance against Skynet and its machines, have been on the run from the authorities following the death of Miles Dyson - something they have been blamed for. Living under assumed identities, Sarah and John eventually realise that the future apocalypse was not averted but merely delayed as Skynet sends more cyborg assassins into the past, all programmed to find and kill John Connor. The most relentless of those is the T-888 known only as Cromartie, a machine who will not rest until John Connor is dead. To compound the threats from the future, there are also forces in the present - such as the FBI - that may spring upon the Connors at any moment, further complicating matters and disrupting the mission to destroy Skynet, in order to apprehend them for crimes they didn't commit. However, with the aid of Cameron - an advanced, reprogrammed Terminator - and Derek Reese - John's paternal uncle - it seems that Sarah and John Connor stand ready, more than ever before, to stop Judgement Day.
This theme underwent unification somewhere around the middle of the first season, just after Derek Reese began living with the Connors. There are no significant modifications.