This is a Storyville documentary from 2012 about the Anonymous movement, which was at the height of its powers at the time. With interviews from some of the leading players and analysts the programme focuses on the origins of Anonymous on 4chan.org, and its emerging as a group of Hacktivists that had focused opponents, like the Scientology group.
It seems really to have started out as a group of modern-day pranksters that eventually became politicised when they found they had to fight back against forces that were trying to bring them down, especially after they aligned themselves with Wikileaks.
They also enabled activists in the Middle East when their governments tried to stop the wave of protests during the Arab Spring movement of 2011 by shutting down internet access. The group, being technologically adept, were able to show people how to get services back up and running.
The leadership of the movement seems to have been subsumed by the LulzSec group for some time, which in many ways seems to have been opposed to the principles of Anonymous, though using the same techniques, but used more extreme methods against their opponents.
The end of the film shows the time when the FBI was just closing in and taking down and prosecuting some of the most active members of the group, which was then in its early stages. Eventually the movement seems to have ended in any recognisable form, and their last major actions were probably in 2016.