Brothers Beau, John and Digby Geste join the Foreign Legion, where they fall under the rule of tyrannical Sergeant Markoff. Beau and John are assigned to Fort Zinderneuf, where Markoff tries to break their spirit, aware of a dark family secret concerning a fabulous jewel one of them carries. As tensions rise, Arabs attack the fort and rivalries must be thrown aside in a desperate battle for life.
A relief column led by Major de Beaujolais approaches Fort Zinderneuf, only to find the garrison apparently slaughtered. Legionnaire Digby Geste offers to climb in to investigate,…
The brothers have returned to Brandon Abbas from university, when a valuable family heirloom, the 'Blue Water' sapphire, goes missing. Lady Brandon is reluctant to call the police…
To protect Michael, Digby also departs, taking the blame in a note left for John; John, though, guesses that they will have both gone to join the French Foreign Legion, and quietl…
The brothers are reunited after being sent to Oran with a draft of new recruits. Their Sergeant-Major, Lejaune, takes a disliking to the trio, and also to two American recruits, H…
Boldini informs Lejaune that Michael has a stolen jewel on him. After Boldini fails to talk two recruits to steal it for him, Lejaune himself persuades former pickpocket Bolidar t…
The column marches across country to Fort Zinderneuf; once there, Lejaune has Hank, Buddy and Digby sent to a further post. Lejaune's harsh treatment, and promotion of Boldini to …
Some of the men are on the edge of mutiny when the fort comes under repeated attack from the Tuareg. Before being killed, Michael reveals he has some letters and a parcel for his …
John kills Lejaune in the struggle, and then flees the fort on the approach of the relief column. Digby finds Michael's body and, remembering a childhood promise, gives it a Vikin…