Egypt 1942. The British 8th Army has retreated almost to the Nile under the onslaught of the German Afrika Korps. Shipwrecked on the Red Sea coast is a party of refugees from the Soviet Union. Among them is one person vital to the Allies' war effort. The person has specialist knowledge of how the German encoding machine, Enigma, can be broken and German secret ciphers read. A British army officer is given the mission of rescuing the refugees and ensuring that this person does not fall into German hands. In a race against time the officer must ensure the safety of the refugee and combat enemy and other forces working against him to use the knowledge the refugee possesses for their own ends.