COBRA is assembled when fresh disaster strikes - a breach at Dover port means an insidious threat may be in play. As Sutherland is briefed by his team, the mission is set; intercept any trucks which made it through the breach, whilst avoiding mass panic.
Following the latest shocking discovery, the team scramble to understand what it means. It's clearly a message, but who is the sender? Meanwhile, Francine's TV attack on Lord Singer is met with delight by Labour leader Chris Edwards. It is also seized upon by online presence Firestorm, to Francine's discomfort.
Rachel Sutherland is dismayed by the fresh media assault on her reputation, but Robert is distracted - for somehow, Firestorm is back, and spreading misinformation about the water supply. Anna and Eleanor placate the seething PM, but when reports of new cyber attack chimes with Archie's theory that a proxy war is underway, he demands they hit back at Russian and Chinese targets.
Reeling from the events in Kent, the COBRA team are briefed by Eleanor on the nature of a sophisticated malware which has infected the UK's critical infrastructure. An urgent response is needed if they are to avoid total calamity, but with Anna gone and dissent rising amongst the ranks, Robert grapples to make the right decision