The Sidewinder Syndicate's ancestors were stranded on Old Earth in Chicago during the 1920s and adopted the methods and mannerisms of the Chicago gangsters enthusiastically. (AUDIO: House of Cards) The Tenth Doctor met the Sidewinder Syndicate during a visit to a bar in America. The Syndicate attacked the bar, then left. The Doctor, Heather McCrimmon and Wolfgang Ryter tracked them down to a shop in the city were they were met by Snake-Eyes. The Doctor sent them home in their ship by scaring them with an animal picture book which included sharks and lions. (COMIC: Snakes Alive!)