Serial: Z  Episode Nos. 115, 116, 117, and 118.  Title: The Gunfighters

The TARDIS lands in Tombstone, Arizona on the eve of the infamous gunfight at the OK Corral, and the crew can’t help but get involved in the fighting between the Earps, the Clantons, Doc Holliday, and Johnny Ringo.

starring William Hartnell as Dr. Who, Peter Purves as Steven Taylor, and Jackie Lane as Dodo.  Written by Donald Cotton, Produced by Innes Lloyd, Directed by Rex Tucker.

Originally transmitted from 30 April 1966 to 21 May 1966 on BBC1.