Episode 4 of "Zero Day" kicks off with the colossal bank, American Homestead, being besieged by a cyber onslaught. In a bid to halt the escalating digital assault, the government imposes a blanket freeze on all financial transactions. However, this drastic measure backfires spectacularly, leaving the local populace penniless and sparking widespread riots that grip the city in chaos.
Amidst this turmoil, Dreyer strives to wrestle control of the bank crisis from Mitchell's steadfast grip, but to no avail. Elsewhere, George finds himself locked in a grueling interrogation with Evan Green, whose collaboration with the Reapers is increasingly substantiated by fresh evidence. Green maintains his arrogant, evasive demeanor, defying any attempt to pin him down. His attorney, Bob, tries in vain to drive home the gravity of the situation, warning that his client's human rights would be nullified under the commission's arrest. Bob insists that even if Green merely extended an invitation to the Reapers as guests on his show, he must come clean. The erasing of his hard drive prior to his arrest only deepens the shroud of suspicion.
The commission finds itself mired in a public relations quagmire, with negative rumors spreading like wildfire, fanned by CEO Monica Kidder's clandestine maneuverings. Even the media outlets that once championed George now label him ineffective. Melissa, desperate to alter the narrative, suggests that George testify to portray him as open and transparent. Yet, he resists until they unearth concrete answers. Their next strategic move is to invite Kidder to the table, though her ulterior motive seems merely to secure a seat of power.
Meanwhile, a desperate Valerie seeks audience with Mr. McKenna, the pioneering scientist behind Proteus. With all other experts deceased, someone has inexplicably reactivated this neurological weapon, a stark violation of the Geneva Accords. Proteus has the capacity to inflict brain trauma remotely, its origin untraceable due to its utilization of radio waves, making it a silent, invisible menace.
On the twentieth day, Green at last engages in conversation with Carl, steadfastly maintaining his innocence and claiming possession solely of the Reapers' emails. Meanwhile, Valerie unveils the findings from the scorched Idaho server farm, revealing a pair of code names that strike Roger with astonishment, as he recognizes them from his time aboard Lyndon's yacht.
Valerie then enlightens George about Proteus, stunning him considering his office was responsible for dismantling it. She delineates its symptoms: dementia, psychosis, sleep deprivation, stress, mood swings, impulsivity, hallucinations, and memory blanks. As he confesses to experiencing these very symptoms, they realize he has been marked as a target.
Roger, unwittingly delving deeper, inspects the radio equipment discovered at the Idaho farm. He purchases a fresh radio and tunes it to the last frequency it was on, seeking answers.
Elsewhere, Dreyer persuades Mitchell that George must resign to shield her from any potential repercussions, invoking George's prior withdrawal from the reelection due to his son's demise. Dreyer subtly suggests that another such tragedy could prompt George's departure once more, leaving one to ponder: could Dreyer be contemplating Alex's demise?
Alex confides in Sheila, expressing her concern for George. Outside George's residence, Green and Kidder's supporters stage a protest, prompting Sheila to take decisive action.
George's eventual meeting with Kidder is charged with tension; her ego is visibly bruised by his initial rejection of her assistance. He wastes no time, confronting her directly about the harm she is inflicting on the nation and the benefits she reaps from it. He presents her with an ultimatum: either she aids them in soothing the public's unrest or she exits the scene.Mitchell informs George that he has a mere 24 hours to uncover a connection between the bank attack and Zero Day; otherwise, she intends to thaw the frozen financial infrastructure, much to his dismay. Confident in her belief that the two incidents are unrelated, she cites Dreyer's possession of evidence pointing to a similar bank assault last spring. George is incensed with Dreyer for withholding such crucial information. Furthermore, he suspects the presence of the Zero Day malware within their financial servers, an assertion Mitchell fiercely disputes.
Roger overhears a coded message being broadcast on the radio and jots it down hastily. He contacts Alex, longing for a way to escape their current predicaments before venturing into a bar. Soon afterward, Lyndon's emissary arrives, instructing Roger to orchestrate George's resignation by presenting evidence of George's mental instability. Failure to comply, the emissary warns, will result in the revelation of Roger's darkest secrets to Alex.
Sheila arrives at headquarters, only to be briefed about Proteus. She urges George to step down, but he steadfastly insists on his well-being. Skeptical of his claim, she insists on a psychological evaluation.
Meanwhile, Roger delves into George's journal, uncovering evidence of his mental instability. Armed with this newfound knowledge, he heads to Alex's place, where they both drown their sorrows in alcohol. Roger reminisces about their shared memories and confesses his undying love for her, revealing that it was she who secured his job with George. He also admits to hacking her phone and publicly exposing her ex as an act of desperate love. Alex is left stunned as Roger staggers out of her place.
Back at his home, Roger refuses to be manipulated by Lyndon's men. It's a fatal mistake; moments later, a group of thugs burst in, dosing him with drugs and drowning him in his bathtub.
George's psychological evaluation proceeds smoothly, save for one peculiar question. Asked if any music is playing, he denies it despite the silent room, for he can hear 'Who Killed Bambi' echoing in his mind—this time, acutely aware that it's a symptom of Proteus. The evaluation results confirm George's sanity, revealing that Proteus only takes control at specific intervals. Sheila is disheartened, realizing that George's missteps are indeed his own doing.
He has squandered so much time that his concern has reached its limit. Desperate to expedite matters, he orders Carl to subject Green to torture, hoping it might yield some answers. Yet, it appears that Green is indeed innocent of any knowledge, but George remains unrelenting in his brutal interrogation, blissfully unaware of Green's motive to erase his hard drives – a desperate attempt to cover his tracks in a money laundering scheme.
The following morning, Mitchell receives a chilling tip: the bank attackers are none other than the Sinecure, the same bunch who struck last spring. Alex is left reeling from the tragic news of Roger's demise, while George succumbs to PTSD, haunted by the memory of his son's fatal overdose, accompanied by the haunting tune of 'Who Killed Bambi' playing on his radio. Now, as he inspects Roger's bathroom, George is struck by the eerie similarity to his son's final scene, cluttered with drugs. It dawns on him that Lyndon's men have cleverly staged Roger's murder to resemble a drug overdose.
By the conclusion of Zero Day Episode 4, George finds himself engrossed in introspection, his eyes glazing over his journal, its contents resembling the delirious scribbles of a madman. Frustrated, he slams the journal shut and conceals it deep within his drawer, burying his troubled thoughts along with it.
