Diego is one of the chiefs of the Spanish Communist Party. On his way from Madrid to Paris, he is arrested at the border for an ID check but manages to get free. When he arrives in Paris, he starts searching for one of his comrade to prevent him from going to Madrid where he could be arrested.

An FBI agent works with a refugee scientist and the Coast Guard to crack a Soviet spy ring in Boston.

Rafa, a Communist Republican exiled after the Spanish Civil War, returns to his hometown to carry out an attack against the imposed tyrannical regime, but the mission fails and, in his attempt to escape, he kidnaps a lady of high society.