While Blake is in Europe, a revolution starts in San Diablo between a Communist faction and a democratic faction. Because of the fighting, there is a shortage of medical help in San Diablo, and several American doctors, including Dr. Donald Blake (with his trusty sidekick, nurse Jane Foster), agree to go there to help. However, the evil Executioner, leader of the Communist faction, does not want the peasants to be treated. He wants them to remain ill so that they will be too weak to oppose the Communists.


