The Sergeant of the Yukon was a radio series entitled “Challenge of the Yukon” that later became an action TV series on 1955. The story was about Sergeant William Preston with his Alaskan dog named Yukon King that fights against bad people. Preston was a police from Royal Canadian Mounted Police and had the job to patrolled in the Northern during Gold Rush. The true star of the show was the brave Yukon King did more work that Sgt. Preston like helping injured trappers, tracking smugglers or saving dwellers from wolves. During his summer months his horse Rex was more useful in helping him in his cases. Richard Simmons played the part of Preston. It was aired on CBS channel and ended after three years of continuous running.