Algeria 1957. In the heart of the war that pits the French troops and the rebels fighting for the independence of their country against each other, an event occurs which is worrying in the extreme for French headquarters: a fortnight ago a platoon of twenty-two men disappeared with their weapons and luggage. This platoon, consisting or Harkis, Algerians enrolled in the French army, was under the command of lieutenant Messonnier. Captain Valéra, charged with finding Messonnier and his section, leads the inquiry into the Kabyle mountains, to the same spot where the section disappeared. Have Messsonnier and his men defected to the enemy? Was the platoon wiped out by the armed groups of the F.L.N., the Algerian Front de Libération Nationale? Was Messonnier betrayed by his second in command, Mohan Djeddar, who was an F.L.N. militant before he joined the French army? A strange person, this Messonnier…