Star Trek: Season 1, Episode 9

Dagger of the Mind (3 Nov. 1966)

TV Episode  -   -  Action | Adventure | Sci-Fi
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Ratings: 7.5/10 from 947 users  
Reviews: 10 user | 8 critic

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.



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Title: Dagger of the Mind (03 Nov 1966)

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


When a psychologically disturbed member of the staff of the Tantalus penal colony, Dr. Marcus Van Gelder, manages to escape onto the Enterprise, Captain Kirk and Dr. Helen Noel beam down to the planet to see exactly what is going on there. The head of the prison is a renowned penologist, Dr. Tristan Adams, greatly admired for the advances he has made in treating criminals. While Dr. Noel can find no fault with Dr. Adams or the practices at the colony, Kirk isn't so sure. Mr. Spock must use the Vulcan mind meld on Van Gelder to get to the truth. Written by garykmcd

Plot Summary | Plot Synopsis


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Release Date:

3 November 1966 (USA)  »

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Aspect Ratio:

1.33 : 1
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Did You Know?


Lethe (Susanne Wasson) was named after the river in Hades in Greek myth. Those condemned souls who drank from it, forgot their past lives. Explaining her blank, vegetative stare from neutralizer "treatment". See more »


When Van Gelder enters the bridge and demands asylum, the close up shots use red lighting on the actors. In the wide shots, the lighting is normal. See more »


Mr. Spock: What did he do to us?
Dr. Simon van Gelder: He can reshape any mind he chooses. He used it to erase our memories, put his own thoughts there. He was surprised it took so much power. We fought him, remember? But we grew so tired. Our minds so blank, so open, that any thought he placed there became our thoughts. Our minds so empty, like a sponge needing thoughts, begging, empty. Loneliness. So lonely to be sitting there empty, wanting any word from him.
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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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