The Time Lord and the Ponds get mixed up in a Wild West adventure as the Doctor becomes the reluctant sheriff of a town being terrorized by a relentless cyborg who goes by the name of the Gunslinger. But who is he and what does he want? It seems the answer lies with a mysterious alien whose initial appearance hides a dark secret.
original airdate--September 15,2012 rating--8.42 million/33.4% share #9
music--theme song "The Chase" by Murray Gold
Main enemy--Kahler-Tek, Kahler-Jex
Main setting--Mercy, Nevada, 1870
Goofs:When the Marshall is killed by the gunslinger the doctor pins the badge to his jacket, between shots the badge moves position several times.
Trivia:Scott Bakula was first offered Issac but dates clashed with other projects.
*UK rating figures