The storyline of Watch Dogs game is built around the concept of information warfare, data being interconnected, and the world's increasing use of technology—questioning who exactly runs the computers they depend on. The game is set in an alternate reality version of Chicago, Illinois, which is one of many cities to feature a supercomputer known as a "CtOS" (Central Operating System). The system controls almost every piece of technology in the city, and contains information on all of the city's residents and activities which can be used for various purposes.In the game's universe, the Northeast blackout of 2003 was found to be caused by a hacker, prompting the development of CtOS. The game will follow an antihero named Aiden Pearce, a highly skilled hacker described as a person who uses both "fists and wits. The gameplay demo shown at E3 2012 depicted Aiden's attempt to assassinate a media mogul named Joseph DeMarco, who had been wrongly acquitted on charges of murder.
In demonstration shown E3 2013, the story involves the character 'T-Bone' contacting Pearce for help after he is almost caught stealing an illegal motherboard. T-Bone is forced to leave the motherboard so the police can track the CtOS movement. Pearce rescues T-Bone, but gets surrounded by police, however he is able to hack the power grid to distract the police and escape.