A missing submarine in Spanish Civil War leads to the first German Navy operation before WW2. Republican submarine C-3 was the victim of international secrecy and intrigues, after a torpedo from U-34 sunk it on December 12th 1936.

This documentary is the result of a strong research in archives and personal memories, for an investigative film which is also an international co-production. The story of a missing submarine of the Spanish Republican fleet, the C-3, had all the ingredients for such a film: its records had been manipulated at the Spanish Navy archives (to disguise the acquisition of an Italian fascist submarine, by Franco, when international laws forbid it, during the Civil War), and its memory erased from all the witnesses and families of the crew. After 40 years of dictatorship government, no traces of the truth remained, until the wreck was located by an amateur fisherman and local lawyer. Apart from this "memory recovery" task, the most appealing fact for an international film was the fact that, behind the C-3's disappearance, was the intervention of German u-boots in Spain, in 1936, in combat missions, something totally unknown to historians. This u-boot mission (the Operation Ursula) was the rehearsal of the new submarine warfare for World War 2, and of the new u-boots and torpedoes that the German Navy had been secretly developing to avoid the Versailles Treaty limitations after World War 1. A personal decision of Hitler's, in collaboration with Mussolini, who also sent his own submarines (a more acknowledged fact by historians). So, there was the international dimension both for the research and the film, that is conducted by an American historian from the US Naval School of Norfolk, Mr. Willard Frank, jr, perhaps the best expert in naval warfare in the early thirties and the Spanish Civil War. His own search leads the story of Operation Ursula, from the inquiries at German archives (decoding the secret papers of the German Navy, or meeting eventual witnesses of the U-boot that sunk the C-3), to his experience in Spain, that takes the action to meet the last remnants of this "lost story": the sons of the C-3 crew, who only know can start to understand what really happened to their fathers, and reject the disguising versions that placed them in exile or betrayal to the Republican ideals. After such a long inquiry and high contacts with the Spanish Navy (for their official acknowledge of the C-3 true story), the documentary film was made in co-production with German and Italian partners, in order to enlarge the distribution and achieve better access to services, film archives and funding for the film.—Hergueta, José Antonio

In 1998 a submarine wreck was found under the bay of Malaga. How could such an event (its sinking in 1936) be forgotten after the whole city saw the explosion? Many theories have enlarged the mystery over decades. C3 submarine was the victim of terrible times, a civil war and many international plans to use Spanish waters as a test for Second World War.—Hergueta, José Antonio

Submarine C-3 disappeared in the midst of Spanish Civil War and even if the whole city of Malaga saw the explosion, its sinking became a mystery and provoked unexpected episodes and lots of drama. 60 years later the wreck was found and also the secret mission that Hitler authorized becoming first war action by German u-boots before WW2.