Spectre of the Gun
Kirk ignores an alien buoy that warns the U.S.S. Enterprise that it is trespassing into Melkotian space and continues forward when the Melkots transport Kirk, Spock, McCoy, Scotty, and Chekov to a recreation of Earth's wild west. Here their instruments will not function and they are forced to relive, in "a manner befitting their heritage for trespassing," the shoot-out in Tombstone, Arizona on October 26, 1881.
The U.S.S. Enterprise party is transported to the OK Corral, but as they will not fire on the "Earps," the gunfighters cannot hurt them. Chekov, in the role of Billy Claiborne, is killed and Spock realizes that these events are not really transpiring. Through a series of mind melds, Spock is able to reject the illusions of the hostiles enabling the crew to succeed without shooting at the others. The Melkots are impressed by the peaceful behavior of the U.S.S. Enterprise party and return them, including Chekov, who had been killed in an earlier altercation, to the U.S.S. Enterprise. The Melkots agree to establish contact with the Federation.