In 1902, aristocrat Orlando, Duke of Oxford, his wife Emily, and their young son Conrad visit a concentration camp in South Africa while working for the British Red Cross. Emily is mortally wounded during a Boer sniper attack on the camp. Before passing, she makes Orlando promise never to let their son see war again.Twelve years later, Orlando has formed a private spy network of domestic servants (including his servants, Shola and Polly) employed by the world's most powerful dignitaries. The network's primary goal is to protect the United Kingdom and the British Empire from the approaching Great War. Conrad is eager to fight, but Orlando forbids him to join the British Army and persuades Lord Kitchener, Secretary of State for War, not to let him do so.At Kitchener's request, Conrad and Orlando ride with Orlando's friends, Archduke Franz Ferdinand of Austria and his wife Sophie, Duchess of Hohenberg, through Sarajevo. Conrad saves the Archduke from a bomb thrown by Gavrilo Princip, a Young Bosnia rebel intent on sparking a war. Princip later re-encounters the Archduke's entourage by chance and fatally shoots him and his wife. Orlando learns that the assassination was orchestrated by "The Flock": a group plotting to pit the German, Russian, and British empires against each other. The Flock's headquarters is on an isolated clifftop, led by the mysterious "Shepherd", whose ultimate goal is to achieve Scottish independence; its operatives include Russian mystic Grigori Rasputin, trusted adviser to Tsar Nicholas of Russia.On the Shepherd's orders, Rasputin poisons Nicholas's young son Alexei, only to cure him when Nicholas promises to stay out of the war. Conrad is notified of Rasputin's manipulation by his cousin, Prince Felix Yusupov. Knowing the Western Front will be left vulnerable if Russia exits the war, Conrad delivers this information to Kitchener and his aide-de-camp Major Max Morton, who set sail for Russia. Their ship, HMS Hampshire, is torpedoed by a submarine and sunk. Word of Kitchener's death reaches Orlando, spurring him to travel to Russia with Shola, Polly, and Conrad to kill Rasputin. After a grueling fight, Orlando, Shola, Conrad, and Polly successfully kill Rasputin at a Christmas party hosted by Felix. After celebrating his 19th birthday, Conrad expresses his determination to join the army, much to Orlando's dismay.The Shepherd orders Erik Jan Hanussen, an adviser to Kaiser Wilhelm II, to send the Zimmermann Telegram, hoping to distract Britain and the United States. Although British Intelligence intercepts the message and Polly deciphers it, American President Woodrow Wilson refuses to join the war, citing a lack of concrete proof. The Shepherd recruits Vladimir Lenin and orders his Bolsheviks to overthrow the Tsar and remove Russia from the war, sending an assassin to execute the Romanov family.Conrad is commissioned into the Grenadier Guards against his father's wishes. King George V persuades Orlando to let him have Conrad assigned to London. Determined to fight in the war, Conrad swaps places with a soldier named Archie Reid, giving him the nickname "Lancelot" to send his father a message. Disguised as Archie, a member of the Black Watch, Conrad volunteers for a mission into No-Man's Land to retrieve information from a British agent wounded there. He is mistaken for a German spy upon his return and shot, devastating Orlando, but the information he recovered verifies the authenticity of the Zimmermann Telegram.After Wilson again refuses to enter the war despite Conrad's proof, Orlando learns that Wilson is being blackmailed with footage of being seduced by the Shepherd's agent, Mata Hari, and resolves to recover the original negatives. Upon defeating Hari at the American embassy, Orlando has her cashmere wool scarf identified as made from a rare breed only found in a specific mountainous region. Orlando, Shola, and Polly head there and fight their way inside. The Shepherd is revealed to be Morton, who had faked his death and killed Kitchener himself. Orlando fights and kills Morton with the help of Shola. At the same time, Polly recovers the film and delivers it to Wilson, who burns it and prepares to mobilize the United States for war.A year after the war, Orlando purchases the Kingsman Tailor Shop as a front for his organization. Orlando, Shola, Polly, King George, Archie, and the U.S. Ambassador to the U.K. form the original Kingsmen, each assuming code names from the King Arthur legend to honour Conrad.In a mid-credit scene, Hanussen, having taken on the Shepherd identity, introduces Lenin to the Romanovs' killer: a young Adolf Hitler. (thanks to Wikipedia)