The film focuses on the naval warfare around the Battle of Coronel and Battle of the Falkland Islands during the First World War. It was the last in a successful series of documentary reconstructions of First World War battles by British Instructional Films made between 1921 and 1927.

The mastermind behind a ubiquitous spy operation learns of a dangerous romance between a Russian lady in his employ and a dashing agent from the government’s secret service.