First Aired September 07, 1966
Dr. McCoy discovers his old flame is not what she seems after crew members begin dying from a sudden lack of salt in their bodies.
First Aired September 14, 1966
Captain Kirk must learn the limits to the power of a 17-year-old boy with the psionic ability to create anything and destroy anyone.
First Aired September 21, 1966
The flight recorder of the 200-year-old U.S.S. Valiant relays a tale of terror--a magnetic storm at the edge of the galaxy.
First Aired September 28, 1966
The crew is infected with a mysterious disease that removes people's emotional inhibitions to a dangerous degree.
First Aired October 05, 1966
A transporter malfunction splits Captain Kirk into two halves: one meek and indecisive, the other violent and ill tempered. The remaining crew members stranded on the planet cannot be beamed up to the ship until a problem is fixed.
First Aired October 12, 1966
The Enterprise picks up untrustworthy entrepreneur Harry Mudd accompanied by three beautiful women who immediately put a spell on all the male crew members.
First Aired October 19, 1966
Nurse Chapel is reunited with her fianc?; but his new obsession leads him to make an android duplicate of Captain Kirk.
First Aired October 26, 1966
The Enterprise discovers a planet exactly like Earth, but the only inhabitants are children who contract a fatal disease upon entering puberty.
First Aired November 02, 1966
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.
First Aired November 09, 1966
After the Enterprise is forced to destroy a dangerous marker buoy, a gigantic alien ship arrives to capture and condemn the crew as trespassers.
First Aired November 16, 1966
Spock kidnaps the disabled Capt. Pike, hijacks the Enterprise, and then surrenders for court martial.
First Aired November 23, 1966
At Spock's court martial, he explains himself with mysterious footage about when Capt. Pike was kidnapped by powerful illusion casting aliens.
First Aired December 07, 1966
While Captain Kirk investigates whether an actor is actually a presumed dead mass murderer, a mysterious assailant is killing the people who could identify the fugitive.
First Aired December 14, 1966
The Enterprise must decide on its response when a Romulan ship makes a destructively hostile armed probe of Federation territory.
First Aired December 28, 1966
The past months have left the crew exhausted and in desperate need of a break, but does this explain McCoy's encounter with a human-sized white rabbit or Kirk crossing paths with the prankster who plagued his days at Starfleet Academy?
First Aired January 04, 1967
The Galileo, under Spock's command, crash-lands on a hostile planet. As the Enterprise races against time to find the shuttlecraft, Spock's strictly logical leadership clashes with the fear and resentment of his crew.
First Aired January 11, 1967
A being that controls matter and creates planets wants to play with the Enterprise crew.
First Aired January 18, 1967
For bringing hostility into their solar system, a superior alien race brings Captain Kirk into mortal combat against the reptilian captain of an alien ship he was pursuing.
First Aired January 25, 1967
The Enterprise is thrown back in time to 1960s Earth.
First Aired February 01, 1967
Kirk draws a court martial in the negligent death of a crewman.
First Aired February 08, 1967
Seeking the answer to a century-old mystery, Kirk and crew encounter a vacantly peaceful society under a 6000-year autocratic rule that kills all those it can't absorb.
First Aired February 15, 1967
While on patrol in deep space, Captain Kirk and his crew find and revive a genetically-engineered world conqueror and his compatriots from Earth's Twentieth Century.
First Aired February 22, 1967
Kirk and Spock must save their ship's crew when they are all declared killed in action in a bizarre computer simulated war where the actual deaths must nevertheless occur.
First Aired March 01, 1967
The Enterprise investigates a planet whose colonists should be dead, but are not.
First Aired March 08, 1967
The Enterprise is sent to a mining colony that is being terrorized by a mysterious monster, only to find that the situation is not that simple.
First Aired March 22, 1967
With a war with Klingons raging, Kirk and Spock attempt to resist an occupation of a planet with incomprehensibly placid natives.
First Aired March 29, 1967
Existence itself comes under threat from a man's power-struggle with his alternate self, with the Enterprise's strained dilithium crystals presenting his key to a final solution.
First Aired April 05, 1967
When a temporarily insane Dr. McCoy accidentally changes history and destroys his time, Kirk and Spock follow him to prevent the disaster, but the price to do so is high.
First Aired April 12, 1967
The Enterprise crew attempts to stop a plague of amoeba-like creatures from possessing human hosts and spreading throughout the galaxy.
