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 the problem is fixed.
The Enterprise picks up untrustworthy entrepreneur Harry Mudd accompanied by three beautiful women who immediately put a spell on all the male crew members.
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.
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.
The past three months has left the crew of the Enterprise 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?
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.
For bringing hostility into their solar system, a superior alien race pits Captain Kirk in single combat against the murderous reptilian captain of an alien ship he was pursuing.
The Enterprise travels to Beta III to learn the fate of the U.S.S. Archon, gone missing a century earlier. One member of the landing party disappears, and one returns in a strangely blissful state. Kirk beams down with another landing party; amidst the chaos of "Festival" their hosts asks if they are "Archons." To learn more, Kirk must convince Betan citizens to disobey Landru, the man who has ruled them for 6,000 years - or find those who already resist. But with the Lawgivers everywhere, that task is going to be difficult...
Kirk and Spock must save their ship's crew when they are declared all killed in action in a bizarre computer simulated war where the actual deaths must occur to continue.
While investigating and scanning an uncharted planet, the Enterprise and its quadrant of space are subjected to a violent force that seems to cause a 'blinking out' of everything near them. When the scanners resume, where once there was no life on the planet, now there is one life sign. Kirk, Spock and a security force beam down to investigate and find a man named Lazarus who collapses and is brought aboard the Enterprise for treatment. To complicate things further, the initial phenomenon almost totally drained their dilithium crystals. Starfleet and Kirk suspect this...