Lanky and phlegmatic Chic Williams and his short and resourceful friend Joe Mulga face ten days in the stockade for absconding with five jars of rum from the Quartermaster's stores. At the same time, a British intelligence officer, Sir Guy Gough, is seeking to outwit a German spy ring, run by Von Schieling and a French adventuress. Chic and Joe, Corporal Joe McTavish, and Captain Jack Fisher help trap the spies and gain invaluable information. They are rewarded with ten days' leave in London, where Captain Fisher has a romantic involvement with a young woman named Alison.
