A year has passed since Eggsy Unwin and the secret organisation Kingsman saved the world from Richmond Valentine’s neurological wave broadcast. He has since taken his late mentor Harry Hart’s title of Galahad and lives with Crown Princess Tilde of Sweden. On his way home he is ambushed by Charlie Hesketh, a former Kingsman trainee who lost his arm and vocal cords during the Valentine incident. Eggsy evades Charlie and his henchmen in a car chase across London, but Charlie’s severed cybernetic arm hacks into the Kingsman servers through the car’s computer system. While Eggsy is away in Sweden, a volley of missiles destroy the Kingsman headquarters and wipe out all of the agents in Britain, including Eggsy’s best friend Roxy.
Being the only surviving agents, Eggsy and Merlin follow the Doomsday protocol, which leads them to Statesman, a secret American organisation posing as a Bourbon whiskey distillery in Kentucky. There, they discover that Harry survived Valentine’s gunshot a year earlier, but is suffering from amnesia. Eggsy and Merlin are briefed by Statesman head Champagne about a secret terrorist organisation called The Golden Circle. They begin their mission by following Charlie’s ex-girlfriend Clara Von Gluckfberg. When Statesman agent Tequila develops blue rashes, he is replaced by agent Whiskey as Eggsy’s partner. Eggsy manages to plant a tracking device on Clara during an encounter, but his revelation of the mission to Princess Tilde strains their relationship. After several failed attempts to cure Harry’s amnesia, Eggsy triggers Harry’s memories by threatening to shoot a Cairn Terrier that resembles Harry’s late dog.