During World War II, Germany occupied large areas of Soviet territory and was ready to test missiles and attack Moscow. Soviet pilot Grivtsov, co-pilot Linkov and radio operator Katya were ordered to spy on the enemy, the plane was shot down and the two pilots were captured. Linkov defected and Grivtsov successfully escaped from the prison camp. They must now complete the combat mission and return to the motherland on which they depend for survival.