In Washington, Brigadier General Whitcombe is sitting in his private office at a large oak desk. Standing in front of him is First Lieutenant John O'Brien, who has been his official courier for the past nine years. O'Brien has always been methodical, resourceful and diligent, so the Brigadier has no qualms about sending him on the next important mission. He must hand deliver a package containing highly confidential military plans to the Commander at the San Francisco fortification. So as not to raise any suspicion, the Brigadier wants him to take the Transcontinental train. However, O'Brien won't make it to his destination this time...