A team of Allied saboteurs fight their way behind enemy lines to destroy a pair of Nazi guns.

In 1943, an Allied force becomes trapped on the island of Kheros in the Aegean Sea. The only possible way to evacuate the men is through a small channel dominated by two huge German guns buried deep in the solid rocks of Navarone. Because the guns are impregnable against air or sea attack, a sabotage team of six is sent to Navarone in a desperate attempt to destroy the massive weapons. Security officer Major Franklin leads the commandos, who include: Captain Mallory, a world-famous mountaineer; Corporal Miller, an explosives expert; Col. Andrea Stavros, a Greek resistance fighter; Pvt. Spyros Pappadimos, a New York--educated delinquent who was born on Navarone; and C. P. O. Brown, a veteran knife fighter. After sinking a German patrol boat, the little group loses its own vessel in a violent storm. The men reach shore with their gear, however, and succeed in scaling a sheer cliff face, the only unguarded approach to Navarone. In the ascent Franklin breaks his leg, and Mallory assumes command. The saboteurs then make contact with two resistance fighters (Spyros' sister, Maria, and a former schoolteacher, Anna, who has been shocked into dumbness by Nazi torture). Despite the aid of the two women, the commandos are captured by the Germans. Andrea tricks the Nazi guards, and the saboteurs escape in their captors' uniforms. As they approach the guns, they learn that Anna is a traitor, feigning muteness while supplying the Germans with the group's positions. Realizing she must be killed, Mallory draws his pistol, but it is Maria who fires the fatal bullet. Mallory and Miller then sneak into the fortress and set their explosives, while the others divert the attention of the Germans. Brown and Spyros are killed in the fighting, but the remainder of the group escape to the sea. At midnight British destroyers move into the channel and head for Kheros. As the giant weapons swing into action, a tremendous explosion shatters the entire cliff and the guns of Navarone crash into the sea.