"Dagger of the Mind" is the ninth episode of the first season of the American science fiction television series Star Trek.
In the episode, the Enterprise visits a rehabilitation facility for the criminally insane where the chief doctor has been using a device which destroys the human mind.
[1] The USS Enterprise, commanded by Captain Kirk, makes a supply run to planet Tantalus V, a colony where the criminally insane are confined for treatment.
After the Enterprise delivers supplies and receives cargo from Tantalus, a man emerges from the container taken aboard and assaults a technician.
In sickbay, the intruder identifies himself as Simon van Gelder, and a computer check reveals that he is not a patient, but Dr. Adams's assistant.
She finds that she can easily implant thoughts into Kirk's mind, even altering his memory of a recent Christmas-party encounter between the two of them.
A guard discovers Noel's sabotage, they fight and she defeats him with an athletic kick that sends him hurtling into the electric circuitry, killing him.
Handlen noted Kirk and Noel's relationship as the plot's "weakest element", and that Adams did not make a compelling villain.
On the other hand, he felt that Nimoy made Spock's mind meld sequence "fairly effective".