The plot of Watch Dogs Legion, the latest title in Ubisoft's hack-em-up series, begins with a bang. Things kick off as DedSec, the secretive hacking collective from the previous Watch Dogs games, attempts to prevent a terrorist bombing in the Palace of Westminster. Although they succeed in doing so, they're attacked and nearly wiped-out by those behind the plot, the rogue hacker group Zero-Day, as more bombs detonate across the city, killing thousands.
In the wake of the bombings, the British Government task private military company Albion with restoring order in London. DedSec take the blame for the attacks, as the city descends into a hyper-surveilled police state. However, a single Dedsec Operative, Sabine, survived the attack, and begins recruiting new members to rebuild the organization, with the help of the advanced AI Bagley and leads to the events of the game. NOTE: MAJOR SPOILERS ahead for Watch Dogs Legion.
Shutting Down Themis
Throughout the rest of the game players use Watch Dogs: Legion's unique Play As Anyone system to rebuild DedSec, and take down the major players of new London. The biggest of these is Nigel Cass, CEO of Albion. Toward the end of the story, its revealed that Cass is working on the THEMIS project, a new program to use drones to kill Londoners who are about to commit a crime.
After successfully shutting down THEMIS in Legion's version of Tower Bridge, DedSec decide to attack Cass indirectly by stripping away his support. In the process of this, they learn that Cass was directly involved in the earlier bombings, having partnered with Zero-Day in order to gain control over London. DedSec releases the condemning information to the public, and, when Cass declares himself untouchable, takes him down themselves.
The Ultimate Betrayal
Though DedSec celebrates following their defeat of Nigel Cass, their elation is short-lived. Zero-Day hacks them, stealing the valuable technology that they acquired during the course of the game. Reversing the hack, the DedSec Operatives quickly discover that Sabine herself is Zero-Day, and partnered with Cass to carry out the bombings. The revelation that the woman who restarted DedSec was responsible for its fall from grace in the first place is the biggest twist in Watch Dogs: Legion.
It's then revealed that Sabine had made a deal to allow Albion to take control of the city, in exchange for access to Albion's Filament Network, a powerful computer system. The deal went sour when DedSec unexpectedly defused the Westminster bombs, causing Cass to double-cross Sabine and attempt to kill her. DedSec's new Operatives discover that Sabine's primary motivation in restarting the hacker group was to take revenge on Cass for this double-cross.
Taking Back London
However, vengeance on Cass wasn't Sabine's only motivation in rebuilding DedSec in Watch Dogs: Legion, as the Operatives soon realize that she has a larger plan. She uses the technology they gathered to link a series of AIs to Bagley, plunging the country into chaos by sending their technology haywire. This is all part of the plan that Zero-Day first revealed at the beginning of the story, to force the nation to forgo technology and begin civilization again from scratch.
To prevent Sabine/Zero-Day from carrying out her plan, Legion's DedSec Operatives are forced to shut down Bagley, and kill Sabine when she tries to stop them. In the closing credits, it is revealed that the British Government are reviewing their contract with Albion, and bringing back local law enforcement. DedSec has cleared its name, and been praised for exposing the corruption at the heart of the city. Finally, in a post-credits scene, a single drone containing Bagley's AI returns to DedSec HQ, allowing the Operatives to restore him to his prior state.
Watch Dogs Legion is available now on PC, PS4, and Xbox One, on November 10th for Xbox Series X, and November 12th for PS5.