Shortly before the outbreak of World War II: Leopold Trepper, a colonel in the Red Army, travels to Belgium under a false name and sets up a spy ring there. Together with his employees Viktor Sukulow-Gurewitsch, Johann Wenzel, Hillel Katz and Michail Makarow, he succeeds in establishing a spy network throughout Belgium and France in a very short time. With the help of his cover companies - a chain of raincoat shops and later the import-export company Simexco ”- Trepper can collect information from the economy and the Wehrmacht, about Atlantic Wall construction sites and railway lines, and send it to Moscow. The agents also get help from patriots who want to free their countries from the occupation by the Germans.