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"The Mark of Gideon" was the 72nd episode of Star Trek: The Original Series, the 17th episode of the show's third and final season, first aired on 17 January 1969. The episode was written by George F. Slavin and Stanley Adams, directed by Jud Taylor and novelized in Star Trek 6 by James Blish. A remastered version of this episode was aired in syndication, premiering on 31 May 2008.



Captain's log, stardate 5423.4.
We are orbiting the planet Gideon, which is still not a member of the United Federation of Planets. The treaty negotiations have been difficult because Gideon has consistently refused the presence of a delegation from the Federation on its soil, or any surveillance by the ship's sensors. They have finally agreed to a delegation of one. They insisted it be the captain of the Enterprise. I am, therefore, beaming down at once.
Log entry by James T. Kirk.
I am alone on the Enterprise. I have searched every area of the ship and still cannot find a trace of the crew, or an indication of how its disappearance was managed. The one thing that is obvious is that I suffered a memory lapse, during which time I bruised my arm. It is causing me some irritation.


Ship's log, stardate 5423.8.
First Officer Spock reporting. Obviously the Gideons have transported Captain Kirk onto this replica of the Enterprise to so confuse his mind as to make him susceptible to some extraordinary experiment. It is my intention to locate the captain and warn him before the experiment reaches its conclusion, which logic indicates means the end of the captain's life as he knows it.



Episode characters

Clifford Brent[1]Pavel ChekovFitzgerald (Admiral)HodinJames T. KirkKrodakLeonard McCoyOdonaMontgomery ScottSpockHikaru SuluNyota Uhuraunnamed Gideonitesunnamed 2260s USS Enterprise personnel

Novelization characters

Pavel ChekovFitzgerald (Admiral)HodinJames T. KirkLeonard McCoyOdonaMontgomery ScottSpockHikaru SuluNyota Uhura

Starships and vehicles

USS Enterprise (Constitution-class heavy cruiser)


Gideon (Gideon system, Dorado constellation, the galaxy's Beta Quadrant)

Shipboard areas

USS Enterprise
bridgetransporter room

Planetary locales

replica of USS Enterprise (bridgecorridorengineeringobservation deckquarters, captain's • sickbaytransporter room) • Gideon Council Chamber

Races and cultures


Science and classification

anatomybeamingbirthratecoordinatesdiseaselife spanmatterorbitplanetphysio-cultural reportspacestarstar systemstardatesynchronous orbit

Medical conditions

bruisefeverVegan choriomeningitis

Technology and weapons

autoclavecauterizercommunicatorintercommedical kitmedical tricordersensorsstarshipviewscreentransportertricorderviewing port

Materials and substances




States and organizations

Bureau of Planetary TreatiesFederationStarfleetStarfleet CommandGideon Council

Ranks and titles

admiralassistantbureaucratcaptainchief engineerchief medical officercommandercommanding officercommunications officercouncillordiplomatdoctorengineerExcellencyFederation Starfleet ranksFederation Starfleet ranks (2260s)first officerlieutenantlieutenant commanderhelmsmanmedical practitionernavigatorofficerprime ministerrepairmanrepresentativescientistscience officersecond officerweapons officertactical officer

Other references

armauditoriumBonesbookbootcaptain's logcaptain's log, USS Enterprise, 2268capital citychesscityclothingdiplomacydressFederation membersfetusfingerfive-year missionGideon Council Chambersgovernmenthomeworldhood (clothing)hourjumpsuitlanguagelifeformlog entrylogicmemorynation-statepantsparadisepetticoatpokerpopulationquadrantraces and culturesrankred priorityregulationsandwichship's logship's log, USS EnterpriseStarfleet uniformStarfleet uniform (2260s)sterilesuicidetechnologytitletreatytunicuniformuniverseVulcan neck pinchweapon


years prior to 2268
Kirk contracts Vegan choriomeningitis. (prior to episode/novelization)
stardate 5423.4, 2268 (2260s chronology, 2264–2270 Enterprise voyages)
Enterprise travels to Gideon.
Kirk recalls the Gideon trick. (TOS novel: The Rings of Time)


Related media

Gideon's surface. (ST reference: The Worlds of the Federation)


Video releases


  • Actor Stanley Adams co-wrote this episode after playing the part of Cyrano Jones in the second season TOS episode: "The Trouble with Tribbles".
  • The novelization by James Blish contains a scene where Odona accidentally burns off her finger with a medical instrument, and quickly re-grows the digit. This aspect of Gideonite physiology was not shown in the episode, although it was alluded that they did have a great resistance to injury. The prose version also added a scene where the crew proposes Odana will offer a symbol of illness to those she infects. The characters of Krodak and Fitzgerald were not named in the novelization.
  • Actor Gene Dynarski (Krodak) had previously played Ben Childress and would later play Orfil Quinteros. Richard Derr (Fitzgerald) previously played Commodore Barstow.
  • This episode marks the only time the bridge set was filmed empty, in this case representing the replica Enterprise. TOS episode: "This Side of Paradise" had previously showed the actual Enterprise bridge devoid of personnel, but with a single Omicron Ceti spore plant present.

Notable cast and crew


Episode images

Adaptation images



published order
Previous episode:
Whom Gods Destroy
TOS episode produced Next episode:
The Lights of Zetar
Previous episode:
Let That Be Your Last Battlefield
TOS episode aired Next episode:
That Which Survives
Previous story:
The Cloud Minders
Star Trek 6
Next story:
last story
until Star Trek 7
chronological order
Previous Adventure:
The Shoulders of Giants
Pocket Next Adventure:
The Lights of Zetar
Previous Adventure:
Whom Gods Destroy
Voyages of the
USS Enterprise (NCC-1701)
(2264 to 2270)
Next Adventure:
The Lights of Zetar

External links

  1. This character was not named in the episode but the same actor, wearing an officer's Starfleet uniform, was addressed as Brent in TOS episode: "The Naked Time". The same actor also played the character of Vinci.