The plot of the 1999 dystopian film The Matrix was based around a fake reality. The majority of humanity had been enslaved as human battery packs, connected into a giant computer or machine and used to power a race of artificially intelligent beings. The matrix that gives the film its name was a virtual reality (VR) world that the humans consciousness was plugged into.
The key thing about The Matrix franchise is that those plugged into it think the life that their consciousness is experience is real, when in fact it isn't. They are ignorant to the reality of life outside of the matrix, with most of them unaware that they are “living” within this computer-generated world.
This is a similar story for many young boys and men in the United Kingdom, who are themselves within a database known as the Gangs Matrix. These individuals within the Gangs Matrix have no idea that their names are part of this criminal list that means police can legally stop and search them at will, even if they have never committed any criminal activity or been involved in a gang.