While London Sleeps is a 1926 film about a police-dog, Rinty, who helps Scotland Yard defeat a dangerous criminal organisation known as the Mediterranean Brotherhood that operates out of the Limehouse district of London. Walter Morosco wrote the screenplay and the film holds the distinction of being the first of many films directed by Howard Bretherton. The film was one of several created for Rin Tin Tin, a German Shepherd dog used in films during the 1920s and 1930s. Also starring are Helene Costello as Dale Burke, Walter Merrill as Thomas Hallard, John Patrick as Foster, Otto Matieson as London Letter, George Kotsonaros as The Monk, DeWitt Jennings as Inspector Burke, Carl Stockdale as Stokes, and Les Bates as Long Tom.