In the Alaskan town of Skagway, Sergeant Preston is assisted by U. S. Marines in his dangerous undercover pursuit of a murderous fugitive and the head of a gold smuggling ring. Directed by: Charles D. Livingstone Writers: Tom Dougall, Robert C. Bennett, Fran Striker, George W. Trendle Dick Simmons as Sgt. Preston Yukon King as The Dog Rex as The Horse Lyn Thomas as Madge Dayton Richard Avonde as Capt. Barry Arnold Initially broadcast on February 16, 1956. Canadian Mountie Sgt. Preston patrols the wilds of the Yukon with his horse Rex and his faithful dog Yukon King, battling both the elements and criminals.