Soldiers of Fort Valeau, a Foreign Legion outpost, discover the mutilated bodies of several men from their overdue relief column, ambushed and massacred by Dylaks. Captain Monclaire's radio report to the garrison at Dini Sadazi results in a promise that more soldiers will be despatched to Valeau, from there to mount punitive action against the offenders. But before the reinforcements arrive, the Dylaks send a message to Monclaire - if he does not surrender, they will attack and conquer the fort...