23 user 6 critic

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

Show more on IMDbPro »

Technical Specs


Sound Mix:




Aspect Ratio:

See full technical specs »

Did You Know?


Some of the colony interiors are reused (and redressed) sets left over from the previous episode, Star Trek: The Original Series: What Are Little Girls Made Of? (1966). See more »


When Kirk and Spock are discussing the identity of the penal colony escapee (Dr. van Gelder), the camera angle goes back and forth between them. When looking at Kirk, the background wall (correctly) curves to the right, past communications and the turbolift. But the reverse angle at Spock *also* curves to the right; however, it should curve to the left, towards the main viewscreen. See more »


Mr. Spock: [performing a mind meld] You begin to feel a strange euphoria... your body floats...
Dr. Simon van Gelder: Yes... I began to feel it.
Mr. Spock: Open your mind; we move together... our minds sharing the same thoughts...
See more »

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 »


Theme from Star Trek
Written by Alexander Courage
See more »

Frequently Asked Questions

This FAQ is empty. Add the first question.

User Reviews

The Doctor will Neutralize Your Brain Now
27 June 2006 | by BogmeisterSee all my reviews

This episode deals with the future of penal colonies and treatment of unstable criminals. Though supposedly such places are much better run in the 23rd century, Dr. McCoy obviously feels we are still far from Utopian with such 'cages' still in existence - but he doesn't offer better solutions. An escape from such a colony triggers a routine investigation by Kirk based on vague doubts by McCoy about how the famous Dr. Adams (Gregory) runs the place. Once again, as in "What Are Little Girls Are Made Of?," a starship captain enters the lion's den on his own, with no back-up, except for a female assistant. Unlike that other episode, where the famous Dr. Korby was driven to lunacy by extreme circumstances, no real explanation is given for Dr. Adams' sudden shift to mad experimentation. Early in the episode, it's established that he's a well-known benefactor in the field of penology and psychiatric medicine, accomplishing more in his lifetime than all of mankind previously in these fields. Was he just fooling everyone up until now, hiding such extreme sadistic tendencies as he puts on display in this episode? He comes across as someone on a childish power trip by the 4th act, but there seems to be no motive for this supposedly great man to behave this way.

Gregory is a fine actor and does what he can with a seemingly truncated role, but the one to watch again is Shatner as Kirk. He's the one who defends Adams while debating with McCoy, almost indicating a kind of hero worship for a man who has made great advances in his field. But once down in the underground colony, his detective instincts take over and Adams is now a target. Kirk proves to be very adept at studying human behavior, more so than his expert assistant, and almost immediately something doesn't smell right to him. He's probably convinced when Adams attempts to avoid the room where the Neural Neutralizer is located - Adams is smooth, but against Kirk he has no chance. Also on hand is actor Woodward as Van Gelder, the one driven insane by the mind sapping device; to say his performance is intense is putting it mildly. The actor showed up again in the role of a starship captain in the 2nd season's "Omega Glory." This episode will go down in history (or has already) as the first one with Spock using a Vulcan mind meld (on Van Gelder). It's a testament to Nimoy's acting ability that he infuses such mystique and focus into a scene which could have been sappy & trite. There's also a great scene of Kirk going insane in the little torture room, his crazed laughter signaling the end of an act - it's kind of scary and the audience may think he's permanently damaged going into a commercial break, because we've already seen the loopy Van Gelder. Otherwise, it's another one of those missions which wasn't really a mission, a case which may have been better suited to Starfleet's special investigations unit and is therefore a bit beneath someone who should be exploring the galaxy, looking for new lifeforms.

23 of 25 people found this review helpful.  Was this review helpful to you? | Report this
Review this title | See all 23 user reviews »

Contribute to This Page

Free Movies and TV Shows You Can Watch Now

On IMDb TV, you can catch Hollywood hits and popular TV series at no cost. Select any poster below to play the movie, totally free!

Browse free movies and TV series

Stream Trending Movies With Prime Video

Enjoy a night in with these popular movies available to stream now with Prime Video.

Start your free trial

Recently Viewed