MI7 finds itself in the midst of a significant cyber-attack launched by an unidentified enemy, leading to the exposure of all its active field agents. To mitigate this crisis, MI7 decides to reinstate several of its inactive agents for the mission of tracking down those responsible for the breach. Johnny English, traditionally seen as a geography teacher, shifts his focus to training his youthful students in the skills of espionage. He fervently requests the assistance of his old partner, Bough, who is currently working as a clerk at MI7.
Their investigation takes them to the stunning south of France, where they trace the origins of the cyber-attack. Upon discovering a yacht named Dot Calm anchored in a nearby marina, they attempt a covert approach using a dinghy under the cover of night. Inside the yacht, they stumble upon a complex server network but encounter Ophelia, a Russian operative, who confronts them, forcing their escape.
The following day, English and Bough follow Ophelia as she departs the yacht. In a thrilling sequence, they pursue her through the winding mountainous roads until their vehicle runs out of fuel. Aware of their efforts, Ophelia surprisingly decides to return, leaving them perplexed. Meanwhile, the Prime Minister of the UK (Emma Thompson) is deliberating over a potential meeting with Silicon Valley billionaire Jason Volta (Jake Lacy), who impressively thwarts a hacking attack on the UK's traffic system just as they converse.
While in France, English meets Ophelia at a bar, only for Bough to uncover evidence suggesting her true allegiance as a spy. Despite this revelation, English, smitten with Ophelia, dismisses Bough's concerns. As Ophelia receives orders from her superiors to eliminate him, a twist of fortune occurs when she fails in her attempt, thanks to English's unintentional consumption of a hyperactive-inducing pill. Meanwhile, Bough links the yacht to Volta.
Concurrently, after enduring further cyber-attacks, the Prime Minister and Volta establish a partnership that will be disclosed at the G12 meeting, in which she agrees to store all UK data on Volta's servers to combat the cyber threats. English is tasked with completing a virtual reality simulation of Volta's mansion for infiltration practice but mistakenly wreaks havoc across London, causing chaos and incidental injuries, including tossing a tour guide off a double-decker bus.
While gathering evidence concerning Volta's true intentions using Ophelia's mobile, English is ultimately betrayed by her. In a desperate bid for freedom, he flags down a driving school car, leading to a high-octane chase with Volta back to MI7. However, he mistakenly switches phones and fails to convince both Pegasus and the Prime Minister of Volta's malevolent plans. Frustrated, she dismisses him and proceeds with the G12 summit in Scotland, leaving English at a crossroads.
With a spirited push from Bough, they resolve to thwart Volta's scheme without MI7's backing. They enlist help from Bough's wife, Lydia, the captain of a Navy submarine. Employing this unconventional approach, they breach the meeting's security via coastal entry. In a tense encounter at the lighthouse, Volta reveals his prior knowledge of Ophelia's true identity. Just as Ophelia attempts to take him out, English intervenes but finds himself falling short yet again, allowing Ophelia to evade capture.
At the meeting, as Volta seeks to exert power over G12 leaders by threatening their data, English attempts yet again to intervene. After his second failure, he reaches out to Pegasus, inadvertently initiating a missile strike from the submarine that destroys the Dot Calm yacht. With Volta fleeing towards a helicopter, English, Bough, and Ophelia give chase, racing against time. In a moment of desperation, English hurls a tablet, knocking Volta out, and dismantling his phone to thwart the entire scheme.
Ultimately, English returns to his former life, greeted by his enthusiastic students, reclaiming his status as an unlikely hero.
