During World War 1, just before the Battle of the Marne, Holmes and Watson were sent to the front lines on a secret mission. They soon found themselves sitting in the front seat of a staff car being driven by a sergeant, sloshing their way through the muddy roads toward the sounds of gunfire in the battlefield. There are also two civilians riding in the backseat, Mr. and Mrs. Mayten Morris, Shakespearian actors and friends of Mycroft Holmes. The staff car stops next to a hut, which is used for identification purposes. Just beyond the hut is an old ruined farmhouse, which serves as the General Stanley Morris's headquarters. The General is Mayten's brother. Mayten and his wife Cynthia are there to entertain the troops before the big battle. Holmes and Dr. Watson are there for a different purpose.