The Netflix film Zero Day has surprised viewers with the answer to who is behind the Zero Day attack. Let’s dive into the finale and break down who was behind the attack and why.

Per the official description, the Netflix limited series sees a former U.S. president “charged with finding the perpetrators of a devastating cyber attack that has caused chaos around the country and thousands of fatalities. As disinformation runs rampant and the personal ambition of power brokers in technology, Wall Street, and government collide,” the president’s “unwavering search for the truth forces him to confront his own dark secrets while risking all he holds dear.”

Who were the people behind the ‘Zero Day’ attack?

As a shock to everyone watching, former President George Mullen (Robert De Niro) discovers his own daughter, Alex (Lizzy Caplan) is a part of the group of politicians behind the Zero Day attack, led by Speaker of the House Richard Dreyer (Matthew Modine), with help from billionaires such as Robert Lyndon (Clark Gregg) and Monica Kidder (Gaby Hoffman), according to Netflix’s Tudum.

Once Mullen connects the dots, he’s faced with the decision to out his daughter’s involvement or put the state of the country first, the job current President Evelyn Mitchell (Angela Bassett) tasked him with.

What does Mullen end up revealing about Zero Day?

He then has to address Congress–and the world…and Mitchell advises him not to reveal that politicians were behind the attack to not have things get further out of control. She wants to just blame the attack on the billionaires, and the members of Congress like Dreyer will leave office and/or retire. Dreyer also meets with Mullen and tells him that they will leave office if he doesn’t reveal it, but if not, his daughter will go down too.

With his daughter’s future in the balance–and after having weathered prior grief from losing his son–Mullen decides to tell a whitewashed version of events. But the memory of his son made him realize he needed to tell the truth. So instead, he reads Alex’s prepared confession where she states she is turning herself in. He reveals everyone behind the Zero Day attack. The admission means he’s losing yet another child–this time to the justice system–but the country is safer as a result.

Why Dreyer wanted Zero Day to happen

The true mastermind behind Zero Day, however, seems to be Modine’s Dreyer. He wanted an event that would unite Americans behind a common goal and help Congress get past its stalemate. He turned to Alex and other colleagues for help, and they developed Zero Day.

Was Mullen impacted by Proteus or was his memory/mental state deteriorating?

In the series, Proteus is a National Security Agency-developed weapon that can cause traumatic brain injury at a distance. Even more insidious is that Proteus can’t be traced, making it the perfect weapon. The idea comes up during the series that Mullen was making questionable decisions during the investigation, and forgetting things because someone is using Proteus on him.

One of the biggest stories in Zero Day was the fact that Mullen was having hallucinations and it seemed as if he was having issues with his memory and his cognition could be impaired. He passed a psych evaluation, even though during that evaluation, he wasn’t being truthful about what he was experiencing. But, as Valerie (Connie Britton) thought, his mental state may not have been declining and he may have been impacted by Proteus, which was thought to never have been used after the NSA ditched the project.

So, was Mullen actually having these issues or was it Proteus? The show really doesn’t make this clear. The showrunners want this to be open to interpretation.

“When Noah [Oppenheim] and I designed the season and wrote the show, we made a pact with each another that Proteus was being used, but that it should be open to interpretation,” co-creator and co-showrunner Eric Newman told Tudum. “Our personal belief when we were writing the show was, yes, Proteus was being used on Mullen. Having now watched the show, I’m not so sure.”

What happens to Mullen at the end?

In the end, Mullen seems to be at peace despite the heartwrenching decision.

Co-creator and executive producer Noah Oppenheim told Tudum says Mullen, after returning back to his home upstate and burning his memoir draft, he “accepted the sacrifice of a life in public service, if it’s spent doing the right thing. He may not have much left, but he’s got his integrity. And I think that’s not to be discounted.”

On the reason why he burned the draft of his memoir, Oppenheim said he “probably has realized his decision in the House Chamber is going to define his legacy moving forward, regardless of what he wrote before. So those pages have been rendered obsolete.”

Zero Day is now streaming on Netflix.

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