Adapted from A. E. W. Mason's novel, an Indian prince warns the British colonials of an imminent holy war.
In northwest India soldiers are ambushed by machine guns. Drummer boy Bill Holder (Desmond Tester) is caned for smoking. At the Governor's ball Captain Carruthers (Roger Livesey) advises the Governor (Francis L. Sullivan) about a holy war and kisses his daughter Margaret (Valerie Hobson). Prince Azim (Sabu) is sent from Tokot to Carruthers and orders the men who shot at the British executed. Azim promises to tell Carruthers the truth. Prince Ghul (Raymond Massey) criticizes the fanatical Mullah and plans war. Bill shows Azim how to drum. In a treaty Carruthers asks the Tokot prince to suppress the passage of arms for a small subsidy. Ghul shoots the Prince; but Azim is saved and hides from his uncle Ghul. Azim tells Bill that he wants to be a drummer and is wounded by a man who demands Azim from Margaret; but she defends him with a pistol and treats Azim's arm.
The troops of Carruthers reside at Tokol. Ghul praises Margaret Carruthers and challenges the English to a polo match. Carruthers learns they have forty machine guns. Ghul threatens Muhammad Khan (Amid Taftazani) not to warn the English. After the polo match Ghul has Muhammad Khan arrested. Ghul goes to Carruthers and invites his men to a banquet. Ghul sets up machine guns aimed at benches. The spy of Carruthers is killed. In Peshawar Azim is told of war after the regiment is massacred, but he will gain the throne. Azim tells Bill he must see the Governor and warns him. The Governor asks Azim why he is acting against his own interest and doubts him. Azim goes to Tokol. A spy tells the Governor of the planned massacre, and troops are sent.
Carruthers dines with Ghul while his troops are entertained on benches. Ghul challenges his belief in equal rights. Azim's men overcome guards so that he can beat the big drum. Carruthers sees the machine guns and hits Ghul. Soldiers run, but some are killed. Carruthers takes over a machine gun until he is shot and captured by Ghul. Many on both sides are killed as the British retreat. Ghul shows Carruthers Muhammad Khan in a dungeon. Margaret thanks Azim. Ghul threatens Carruthers as British troops arrive and attack. Dying Muhammad Khan is brought in, and he kills Ghul before Azim enters. In the final scene Prince Azim announces that his friends, the Carruthers, are remaining for a while.
This adventure depicting British domination of India reflects colonial wars that were still going on there, and the film in fact caused anti-British riots in India. The charismatic Sabu portrays a prince more loyal to the British rulers than to his own people while most Muslims are represented as heartless murderers.