A powerful artificially intelligent Earth probe, with a murderously twisted imperative, comes aboard the Enterprise and mistakes Capt. Kirk for its creator.
A transporter accident places Captain Kirk's landing party in an alternate universe, where the Enterprise is in the service of a barbarically brutal empire.
The USS Enterprise encounters the wrecked USS Constellation and its distraught commodore who's determined to stop the giant planet-destroying robot ship that killed his crew.
Very alien visitors to our galaxy attempt to connect with human consciousness but miss, winding up tapping into the regions of human nightmares instead.
While returning to the Enterprise aboard the shuttlecraft, Kirk, Spock, McCoy and a seriously ill Federation diplomat find themselves kidnapped by an energized cloud.
The Federation clashes with the Klingon Empire over mining rights to Capella IV. A sudden coup between its warrior-minded inhabitants forces Kirk's party to flee with the now dead leader's pregnant wife.
To protect a space station with a vital grain shipment, Kirk must deal with Federation bureaucrats, a Klingon battle cruiser and a peddler who sells furry, purring, hungry little creatures as pets.
Kirk, Uhura and Chekov are trapped on a planet where abducted aliens are enslaved and trained to perform as gladiators for the amusement of bored, faceless aliens.
Peaceful, primitive peoples get caught up in the struggle between superpowers, with Kirk unhappily trying to restore the balance of power disrupted by the Klingons.
The Enterprise is guided to a distant, long-dead world where survivors of an extremely ancient race - existing only as disembodied energy - desiring the bodies of Kirk, Spock and astro-biologist Ann Mulhall so that they may live again.
Looking for a missing Federation cultural observer, Kirk and Spock find themselves on a planet whose culture has been completely patterned after Nazi Germany.
Galactic alien scouts capture the Enterprise for a return voyage and a prelude to invasion. Kirk's one advantage - they're not used to their adopted human form.
Responding to a distress signal, Kirk finds Captain Tracey of the U.S.S. Exeter violating the prime directive and interfering with a war between the Yangs and the Kohms to find the secret of their longevity.
Kirk and a sub-skeleton crew are ordered to test out an advanced artificially intelligent control system - the M-5 Multitronic system, which could potentially render them all redundant.