The 5 Shocking Twists Of Zero Day's Ending: Who Really Caused The Cyberattack?

The political landscape of the United States is shattered in the final moments of the Netflix limited series Zero Day, leaving viewers reeling from a masterful web of political intrigue and betrayal. As of December 2025, the series continues to dominate discussions, not just for Robert De Niro’s gripping performance as former President George Mullen, but for its utterly cynical and shocking conclusion.

This article provides the definitive, up-to-date breakdown of the Zero Day ending, revealing the true identities of the conspirators, the dark purpose of the cyberattack, and the final, ambiguous fate of the man who tried to uncover the truth. The series delivers a potent commentary on the dangers of unchecked power and the ultimate corruption of the political elite.

The Key Players: Zero Day Cast and Character Biographies

The six-episode political thriller is anchored by an ensemble cast of high-profile actors, each playing a critical role in the unfolding conspiracy. Understanding their roles is essential to grasping the complexity of the final twist.

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• George Mullen (Robert De Niro): A single-term, former President of the United States. He leads a self-appointed "Zero Day Commission" to investigate the devastating, minute-long global cyberattack, driven by his own personal tragedy and a sense of duty. His mental state, including auditory and visual hallucinations, becomes a major plot point.
• Alexandra Mullen (Lizzy Caplan): George Mullen's ambitious and politically-minded daughter. She serves as a Congresswoman and is initially a key ally in her father's investigation, though her loyalty is questioned by the end.
• Speaker Richard Dreyer (Matthew Modine): The powerful and confident Speaker of the House. He is a key political operator who constantly pushes George Mullen to focus the investigation on a specific domestic militia group.
• Evelyn Mitchell (Angela Bassett): The current President of the United States. She authorizes the formation of the Zero Day Commission but maintains a cautious distance from Mullen's more aggressive investigation tactics.
• Sheila Mullen (Joan Allen): George Mullen's wife. She is portrayed as worried about her husband's deteriorating mental health and the public spectacle of his investigation.
• Roger Carlson (Jesse Plemons): A key member of the Zero Day Commission and a former aide to Mullen. His loyalty and actions are consistently ambiguous, positioning him as a potential suspect.
• Evan Green (Dan Stevens): A mysterious and highly-skilled operative connected to the cyberattack's origins.

Unmasking the Conspirators: The True Architects of the Attack

The central question of Zero Day is not *if* the cyberattack was a conspiracy, but *who* was powerful enough to execute it and *why*. For most of the series, the narrative points to foreign adversaries, domestic terrorists, or a forgotten Russian operative named Kidder.

The Shocking Reveal: A Political Coup from Within

The shocking truth is revealed in the finale: the attack was orchestrated by a clandestine group of high-ranking U.S. government officials, led by two prominent figures: Congresswoman Alexandra Mullen and Speaker Richard Dreyer.

The 'Zero Day' attack itself—a one-minute blackout of all digital communications—was not the end goal. It was a calculated demonstration of power. The conspirators used the immediate political chaos and public fear to push for the passage of the Zero Day Act, a sweeping piece of legislation that dramatically expanded government surveillance and control over digital infrastructure.

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The Corrupt Motive: Power, Control, and the Zero Day Act

The core motivation was pure political opportunism and a desire for unchecked power. Alexandra Mullen and Richard Dreyer saw the cyberattack as a necessary catalyst to bypass democratic processes and enact their authoritarian agenda. The attack created a crisis that allowed them to present the Zero Day Act as the only solution to national security, effectively weaponizing fear against the populace.

The conspirators successfully framed a dead Russian-linked operative, Kidder, as the sole perpetrator, allowing the Zero Day Commission to conclude its work with a neat, politically palatable explanation. This maneuver protected the real architects and ensured the Zero Day Act became law.

The Proteus Mystery and George Mullen's Ambiguous Fate

Two major elements contribute to the series' dark, unresolved conclusion: the mysterious NSA weapon known as Proteus and the final actions of former President Mullen.

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What is Proteus and How Was It Used?

The term Proteus is a critical entity in the series, representing a terrifying level of technological capability. Proteus is revealed to be a highly advanced, secret neurological weapon developed by the National Security Agency (NSA).

• Technological Capability: It is described as a cyber weapon that could potentially manipulate a target's neurological state, causing confusion, hallucinations, and mental deterioration.
• Mullen's Mental State: The show strongly suggests that George Mullen's increasingly erratic behavior, including his auditory and visual hallucinations, was not merely a sign of natural mental decline. Instead, it implies that Mullen himself was a target of a modified Proteus attack.
• The Purpose: By subtly attacking Mullen’s mind, the conspirators could discredit his investigation. If the former President, the head of the Zero Day Commission, appeared mentally unstable, his claims about a high-level conspiracy would be easily dismissed as paranoia.

The Final, Dark Silence of George Mullen

In the final episode, Mullen successfully gathers enough evidence to expose his daughter and Dreyer's conspiracy. He drops the bombshell on live television, a dramatic act of public service and personal sacrifice.

However, the ending is a profoundly bleak commentary on power:

1. The Burning of the Memoir: After his public revelation, Mullen retreats to his secluded estate. He retrieves the draft of his political memoir, the story of his career and legacy, and tosses it into the fire. This symbolic act signifies the destruction of his public legacy and his realization that his entire political life has been tainted by the corruption he tried to expose.
2. The Empty House: Mullen finds his house dark and empty. His wife, Sheila, has left him. This suggests that the personal cost of his actions—or the strain of his mental state—has destroyed his marriage and his private life.
3. The Ambiguity of Triumph: While Mullen exposed the truth, the final scene leaves the audience wondering about the real impact. The Zero Day Act is likely still in place, the conspirators are powerful enough to weather the scandal, and Mullen is left alone, his mental stability questioned, and his life in ruins. The series suggests that even the truth cannot always defeat the deeply entrenched power structure.

The Lasting Impact and Topical Authority of Zero Day

Zero Day is more than just a political thriller; it is a chilling piece of topical fiction that resonates deeply with current global anxieties. The very term "zero day" refers to a cyber vulnerability that is unknown to the software vendor or the public, meaning there is "zero days" to fix it before it is exploited.

The series successfully explores several critical entities that build its topical authority:

• Cyber Warfare: It highlights the terrifying plausibility of a coordinated, nation-state level cyberattack that can cripple infrastructure and society.
• Conspiracy Theories: The show taps into the public's growing distrust of government, suggesting that the greatest threats come not from outside, but from the highest levels of political power.
• The Surveillance State: The Zero Day Act serves as a stark warning about how a single crisis can be exploited to justify the creation of a permanent, invasive surveillance state, eroding civil liberties in the name of security.

Ultimately, the ending of Zero Day is a cynical masterpiece. George Mullen’s victory is a personal one—he found the truth—but his failure is political. He is left to face the personal consequences while the system he fought against remains intact, suggesting that in the modern political landscape, power and corruption are often the true victors.