Eight years have passed since the original film, and Sir Johnny English (Rowan Atkinson) is now honing his martial arts skills in Tibet, trying to atone for a previous failure during a mission in Mozambique. His peace is disrupted when MI7 reaches out, specifically requesting his expertise as one of their informants insists on speaking only with him.
Upon returning to MI7's London headquarters, now known as Toshiba British Intelligence, he meets his new superior, "Pegasus" (Gillian Anderson), who assigns him a critical mission to thwart an assassination plot against the Chinese Premier, set to occur during discussions with the Prime Minister. This urgent information comes from ex-CIA agent Titus Fisher (Richard Schiff), who is located in Hong Kong. Johnny's task involves tracking down Fisher to uncover more about the impending threat.
In Hong Kong, he encounters Fisher, who reveals he is part of a group of assassins dubbed 'Vortex,' responsible for previously sabotaging his mission in Mozambique. Vortex has been contracted to eliminate the Premier and possesses a secret weapon that requires three metal keys to activate, one of which Fisher hands to English before being killed by an assassin posing as a cleaner. The key eventually falls into the hands of Vortex when they ambush Johnny during his flight to the USA. This embarrassment leads to a confrontation with Pegasus, culminating in Johnny mistakenly attacking her mother, believing she was the assassin.
Meanwhile, Kate Sumner (Rosamund Pike), MI7's behavioral psychologist, urges English to delve into his past mission’s details and identify the second Vortex operative, Karlenko (Mark Ivanir), a Russian double agent. In a twist of fate, English finds himself engaged in a high-stakes golf match against Karlenko, who suffers near-fatal injuries. Before passing away, Karlenko ominously suggests that a third Vortex member lurks within MI7.
As MI7 braces for discussions between Britain and China at a fortified location known as 'Le Bastion,' tensions rise. During a dinner, English reveals his suspicions of a mole in their ranks to Simon Ambrose (Dominic West), only to have Ambrose attempt to eliminate him upon realizing Johnny remains unaware of the mole's identity. A tense confrontation unfolds in the restroom, as Colin Tucker (Daniel Kaluuya) confronts Ambrose, who he suspects is the traitor, yet English intervenes and mistakenly believes that Patch Quartermain (Tim McInnerny) is the real traitor, leading to a catastrophic mistake that puts him at odds with his true allies.
After making a narrow escape in Quartermain's modified wheelchair, Johnny seeks refuge at Kate's home, where they uncover chilling information regarding Vortex's possession of a mind-control drug, which leaves victims susceptible to their commands before leading to heart failure. Ambrose, revealed as the last survivor of Vortex, schemes to leverage this drug for an assassination on the Premier in exchange for a hefty sum.
With the clock ticking, Johnny rushes to warn Pegasus but inadvertently ingests the drug meant to manipulate her. Under Ambrose's control, he is ordered to kill the Premier using a cleverly disguised weapon—a lipstick-shaped gun. The ensuing chaos has Johnny grappling with his own actions as Tucker endeavors to disrupt the connection, resulting in a hysterical sequence where Johnny begins dancing instead of complying.
After a heart-stopping showdown where Johnny appears lifeless due to the drug's effects, Kate breathes life back into him with a kiss, prompting an adrenaline-fueled pursuit of Ambrose. In a dramatic climax, Johnny parachutes into action, engaging in a fierce battle with Ambrose inside a gondola lift. Ultimately, he triumphs by destroying the gondola cable, bringing Ambrose's machinations to an explosive end.
Crowning his comeback, English is knighted but discovers too late that he has mistaken a killer cleaner for the Queen. In a comical turn, he chases her down with a tray, only to inadvertently confront the real Queen herself.
In a delightful post-credits scene that pays homage to classic cinema, English finds himself preparing a takeaway for Kate while humorously reimagining a viral cooking moment with leeks, all set to the whimsical tune of "In the Hall of the Mountain King."
