In 1857, freshly-arrived Sandhurst-trained Captain Alan King, survives an attack on his escort to his North-West Frontier Province garrison near the Khyber Pass because of Ahmed, a native Afridi deserter from the Muslim fanatic rebel Karram Khans forces. King was born locally and speaks Pashto. As soon as his fellow officers learn that his mother was a native Muslim (which got his parents disowned even by their own families), he falls prey to stubborn prejudiced discrimination. Lieutenant Geoffrey Heath even moves out of their quarters. Brigadier General J. R. Maitland, whose policy is full equality among whites, learns that King knew Karram Khan as a boy and charges him with training and commanding the native cavalry. The generals daughter, Susan Maitland, takes a fancy to Alan, even falls in love, but the general decides to send her home to England after a kidnap attempt which was foiled by King. King volunteers to engage Karram Khan, the only man who can bring the normally divided local tribes together in revolt, pretending to have deserted.