Heinrich Heldman, a Nazi-hating German forced to serve in Rommel's army, who, as a post-war French Legionnaire, saved hundreds of French lives and feels compelled to prove his allegiance to democracy and young League of Nations worker Lt. Jean Callaux, whose alluring, social-climbing wife Simone has pushed him into volunteering, hoping that it will result in his promotion Lt.
At Paris' Orly field, Bertrand meets three of the other volunteers: middle-aged Capt. Maurice Bonet, an officer stationed at Dienbienphu. During a layover in Hanoi en route to Dienbienphu, Bertrand hopes briefly to see his lover Gisele, the neglected wife of Maj. Guy Bertrand, who spent three years in a World War II German prison camp and resents that he has never seen action. In France, the first to answer Hanoi's call for volunteers is desk officer Capt. Outnumbered by the attackers, De Castries radios Hanoi for help. Colonel Christian De Castries, the French commander of the 13,000 men stationed there, discovers that a Chinese officer has been providing the enemy with explicit information regarding their number and weapons. On 13 March 1954, in the midst of Communist Indo-China, Viet Minh rebels launch a full-scale assault on the French-controlled valley surrounding the fortress Dienbienphu.