Harry (Colin Firth) is a member of the British secret agent organization Kingsman. During an operation, his comrade died unfortunately. Harry gave a badge and a telephone number to his comrade's young son, Eggi (Alex Nikolov), and told him to call this number if he encountered any trouble in the future. However, such an opportunity could only be used once. Seventeen years have passed in the blink of an eye, and the broken family has made Eggsy (Taron Egerton) grew up as a gangster who did nothing all day long. One day, Eggsy, who was arrested for violating traffic rules, used the precious number in his hand. Harry, who came here, discovered his kind nature and high talent under Eggsy's cynical appearance, so Harry decided to cultivate Eggsy into a new generation of Kingsman. What they need to face together is the powerful and evil billionaire Valentine (Samuel L. Jackson).