In the fourth episode of "COBRA" Season 2, the shadow of conspiracy looms large over the U.K., as Eleanor grapples with the reality of state-sponsored attacks. The episode opens with a chilling discovery: the irradiated man found in a truck under Waterloo Station was a victim of plutonium poisoning, a death as gruesome as it is calculated.

Eleanor's suspicions of state-sponsored terrorism find a focal point in the ongoing threats to national security. The assassination of Kostenko and the drilling contract controversy with a Chinese company in the North Sea are prime suspects, but the truth remains shrouded in mystery. The internal threat is equally alarming, with far-right conspiracies like those propagated by the site Firestorm, inciting violence against key government figures.
The episode unfolds with a sense of urgency as Robert, Joseph, Archie, and Lord Singer are assigned additional security measures. The far-right's call for harm against these figures, including Robert's wife Rachel, is palpable. The scandal manufactured around her early work at a law firm with ties to Kostenko casts a long shadow over the Prime Minister's office.
As Robert insists on attending a memorial for the Kent explosion victims, Labour leader Chris Edwards sees an opportunity for Francine to make an appearance, potentially bolstering her political aspirations. However, Francine's TV interview criticizing Singer backfires when the far-right uses it as evidence of a government cover-up.
The episode takes a tragic turn when Lord Singer is brutally murdered, his assassination live-streamed by a Firestorm fanatic. The government's hand is implicated in the conspiracy theories that emerge, further deepening the nation's unrest.
Robert's determination to uncover the mastermind behind Firestorm leads Eleanor to navigate the legal complexities of internet companies. Meanwhile, Robert's desire to expose Hari Misra's source is met with skepticism from Joseph, who questions the wisdom of targeting journalists.
The political intrigue intensifies as Robert discovers Anna's behind-the-scenes maneuvering with Joseph. Accusations of inciting violence against Singer are leveled against Francine, straining her relationship with Anna and Robert. The Prime Minister's trust in his advisers is tested, and Anna's position as an adviser hangs in the balance.
Francine's guilt over Singer's death is compounded by Hari's consolation, who is himself on the brink of disaster. His possession of a CIA document about a "sub-aquatic detonation system" leads to a harrowing encounter with unknown assailants who question his loyalty and his sources.
The government's successful apprehension of Firestorm's mastermind offers a glimmer of hope, but the mystery deepens with the discovery of subsonic frequency data from the Navy ship's sensors. The implications of this finding hint at a technologically advanced threat beyond the scope of conventional terrorism.
The episode culminates in a shocking revelation: Hari's life takes a deadly turn when he is abducted, interrogated, and ultimately killed, his office firebombed in a chilling act of violence. The irradiated man's identity as a DARPA scientist adds another layer to the complex web of international intrigue.
As the episode draws to a close, the threads of conspiracy, state-sponsored attacks, and internal threats converge, leaving the audience with a sense of foreboding. "COBRA" Season 2 Episode 4 masterfully weaves a tale of political intrigue, where trust is a luxury, and the truth is as elusive as it is vital for the nation's survival.