Episode Title: "DAGGER OF THE MIND"
Production Number: 11
Original Air Date: 11-03-66
The U.S.S. Enterprise is transporting cargo to the Tantalus Penal Colony on Tantalus Five. The crew beams up a crate containing classified research material bound for the Central Bureau of Penology at Stockholm, but one of the penal colony's prisoners has stowed away in the crate, and gets loose aboard the Enterprise.
The Enterprise crew captures the man, and learns that he is Dr. Simon van Gelder, a director at the Tantalus Colony, assigned there six months ago as an associate of Dr. Tristan Adams. The Enterprise returns to Tantalus Five and Captain Kirk beams down to investigate the penal colony with Dr. Helen Noel, a member of McCoy's staff with psychiatric and penology experience. Dr. Adams tells them that Dr. van Gelder's mind was damaged while experimenting with a mind-control beam on himself. Kirk and Dr. Noel later sneak into the treatment room to experiment with the beam themselves, but they are captured by Dr. Adams, who uses the beam on Captain Kirk.
Aboard the Enterprise, Spock uses an ancient Vulcan technique to probe into van Gelder's tortured mind, requiring him to make pressure changes in van Gelder's nerves and blood vessels by touching his face.
In the penal colony, Dr. Noel is able to crawl through an air duct to the power control room and disable power to the colony's security screens, allowing Spock to beam down with a security team. With the power off, Kirk knocks out Adams and escapes from the mind-control beam. Dr. Adams is alone under the beam when power is restored and, with no instructions for his blank mind, he is dead by the time anyone finds him.
Dr. van Gelder is left in charge of the penal colony, and he dismantles the device in the treatment room.
Factoid: Captain Kirk met Dr. Helen Noel at the Science Lab Christmas party.
Dr. McCoy: "He's dead, Captain."
Guest Characters: *Dr. Simon van Gelder, *Dr. Tristan Adams, *Dr. Helen Noel, Lt. Leslie
KEY: [brackets]=illusions *star=first appearance