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Dagger of the Mind 

Kirk and psychiatrist Helen Noel are trapped on a maximum security penal colony that experiments with mind control and Spock must use the Vulcan mind-meld to find a way to save them.


Vincent McEveety


Shimon Wincelberg (as S. Bar-David), Gene Roddenberry (created by)




Episode complete credited cast:
William Shatner ... Capt. Kirk
Leonard Nimoy ... Mr. Spock
James Gregory ... Dr. Tristan Adams
DeForest Kelley ... Dr. McCoy
Morgan Woodward ... Dr. Simon van Gelder
Marianna Hill ... Helen Noel
Nichelle Nichols ... Uhura
Susanne Wasson Susanne Wasson ... Lethe
John Arndt John Arndt ... First Crewman
Larry Anthony Larry Anthony ... Transportation Man
Ed McCready Ed McCready ... Inmate
Eliezer Behar Eliezer Behar ... Therapist (as Eli Behar)


After a psychologically disturbed patient from the Tantalus penal colony, Dr. Simon Van Gelder, manages to escape to the Enterprise, Dr. McCoy begins to suspect that something is amiss on the colony. Captain Kirk and Dr. Helen Noel beam down to the planet to investigate. Written by garykmcd

Plot Summary | Plot Synopsis


TV-PG | See all certifications »






Release Date:

3 November 1966 (USA) See more »

Also Known As:

Dagger of the Mind See more »

Company Credits

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Technical Specs


Sound Mix:




Aspect Ratio:

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Did You Know?


This is the first episode to establish that the transporter cannot penetrate a force field. See more »


Transporter Operator Berkley is credited as an ensign, but the uniform is clearly that of a Lieutenant. See more »


Captain James T. Kirk: Bones, are you aware that in the last 20 years, Dr. Adams has done more to revolutionise, to humanise prisons and the treatment of prisoners than all the rest of humanity have done in 40 centuries? I've been to those penal colonies since they begun following his methods, and they're not cages any more.
Dr. McCoy: Jim...
Captain James T. Kirk: They're clean, decent hospitals for sick minds.
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Alternate Versions

Special Enhanced version Digitally Remastered with new exterior shots and remade opening theme song. A highlight of the new special effects is a new exterior shot of the penal colony, replacing a re-used matte painting from another episode. See more »


Referenced in After Trek: Lethe (2017) See more »


Theme from Star Trek
Written by Alexander Courage
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User Reviews

Nice to See Marianna Hill again
28 November 2006 | by prfrmrSee all my reviews

I rather liked this episode for the particularly fact that actress Hill appears in it, in a rather strong, fluctuate role as Dr. Helen Mirren; psychologist. I have always loved Marianna Hill's work, especially in many of the 60's and early 70's films and TV appearances she's endured, including co-starring with Clint Eastwood in 'High Plains Drifter'.

Hill is remarkably well-done in this one-time episode. In a few scenes she appears slightly apprehensive, almost insecure, far as her abilities as an actress. But nonetheless, she is a great screen beauty, and as fine an actress as any. I especially appreciate that Roddenberry did not subject her character -Mirren- to the typical fawn-femme typecast, as was generally typical of Star Trek women (aka: Kirk's ladies). Her character is independent, strong, and viral. She, and including in her character, holds her own throughout the episode, and displays some of the strongest of female subject, not usually common, for 1960's television.

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