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.



(as S. Bar-David), (created by)

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Episode complete credited cast:
Susanne Wasson ...
John Arndt ...
Ingenieur Fields
Larry Anthony ...
Ed McCready ...
Eliezer Behar ...
Eli (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


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Release Date:

3 November 1966 (USA)  »

Company Credits

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Technical Specs


Sound Mix:


Aspect Ratio:

1.33 : 1
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Did You Know?


Doctor Helen Noel, a former Christmas affair of Captain Kirk, was named after the most beautiful woman in Greek mythology, Helen, and the French word for Christmas, Noël. See more »


When Van Gelder reaches the Enterprise's bridge, he attacks and disables a security guard. McCoy is on the bridge at the time, but even after Van Gelder is subdued, he never so much as glances in the unconscious guard's direction. See more »


Captain James T. Kirk: One of the advantages of being a captain, Doctor, is being able to ask for advice without necessarily having to take it.
See more »

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User Reviews

The Vulcan mind meld
9 April 2009 | by (Italy) – See all my reviews

Dagger of the Mind has everything one would expect from a good Star Trek episode: suspense, great dialogue and a subtle reflection on a contemporary issue, in this case the medical treatment of insane people.

The Enterprise is orbiting around a planet that serves as a prison colony, specifically designed for the criminally insane. When an inmate manages to get on the ship, Spock and McCoy do everything in their power to capture him, while Kirk and the crew's psychiatrist, a woman with whom - what a surprise - he appears to have a history, beam down to the planet to talk to Dr. Adams, whose revolutionary discoveries are well known throughout the galaxy. The truth, it turns out, is rather different from what they thought: the escaped convict is actually someone who used to work at the facility, and has been driven mad by Adams' latest creation, a device that allows him to control the human mind. And now, in order to protect his secret, the doctor intends to use it on Kirk.

The episode originally aired at a time when psychiatric hospitals and various forms of treatment for mentally ill patients were still a controversial subject (Frederick Wiseman's harrowing documentary Titicut Follies, which was banned for its explicit look at what goes on in a "mad house", was released in 1967), and so the writers used the excuse of Trek being nothing but an average sci-fi show - which Gene Roddenberry always stressed it wasn't, and still isn't - to get away with their own look at the issue, hidden under the usual mix of thrills and wit.

Fans also remember Dagger of the Mind fondly because it introduces the famous Vulcan "mind meld", which is essentially a form of telepathy used by Spock to get information when all other methods have failed. It adds a lot to the alien nature of the character, and went on to become a recurring element throughout the series. An iconic moment, and undoubtedly one of Leonard Nimoy's best on the show.

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