09/15/73 -- Stardate: 5373.4
During a trip through the Guardian of Forever time portal, Spock's past is accidentally
changed, and he must travel back into his own past and save his younger self.
One of Our Planets Is Missing
09/22/73 -- Stardate: 5371.3
The Enterprise encounters a cloud creature that feeds on the energy of planets in its
path, but Spock mind melds with the entity and persuades it to return to its place of
The Lorelei Signal
09/29/73 -- Stardate: 5483.7
Investigating a sector of space where starships have disappeared every 27 years, the
Enterprise finds a race of beautiful women who survive by drawing the energy from the men
on the ships they have captured.
More Tribbles, More Troubles
10/06/73 -- Stardate: 5392.4
The Enterprise again crosses paths with Cyrano Jones, who this time has tribbles that
do not breed, but that do grow to a tremendous size.
10/13/73 -- Stardate: 5143.3
Patrolling near the Neutral Zone, the Enterprise finds a ship manned by Carter Winston,
a Federation citizen who has been missing for 5 years; but Winston turns out to really be
an alien who can transform its shape at will.
The Infinite Vulcan
10/20/73 -- Stardate: 5554.4
On a recently-discovered planet, the Enterprise crew meets Dr. Keniclius, a scientist
from Earth's Eugenic Wars, who kidnaps Spock and makes a giant clone of him with the
intention of forcing peace on the galaxy.
The Magicks of Megas-Tu
10/27/73 -- Stardate: 1254.4
While exploring near the center of the galaxy, the Enterprise stops at Megas-Tu, a
planet where magic and witchcraft are the norm, and their guide is Lucifer of Earth
Once Upon a Planet
11/03/73 -- Stardate: 5591.2
Arriving at the shore leave planet for some relaxation, the Enterprise finds that the
planet's keeper is now dead and the untended machinery is constructing dangerous images
from the crew members' thoughts.
11/10/73 -- Stardate: 4978.5
A love potion concocted by Harry Mudd is accidentally spread through the Enterprise's
ventilation system; but a side effect of the potion is that, as it wears off, the affected
persons hate each other.
The Terratin Incident
11/17/73 -- Stardate: 5577.3
While exploring a burnt-out supernova, the Enterprise finds a miniature city called
Terratin, and soon discover that it is a lost Earth colony that has mutated because of the
supernova's radiation and that the Enterprise crew is beginning to shrink also.
11/24/73 -- Stardate: 5267.2
Caught in an ion storm, the Enterprise and a Klingon battlecruiser are drawn into a
time warp called the Delta Triangle and must cooperate in order to escape it.
The Ambergris Element
12/01/73 -- Stardate: 5499.9
While exploring the planet Argo, Kirk and Spock are made into waterbreathers by an
undersea race, and the venom of a deadly sea snake is the only antidote to return them to
their normal selves.
12/15/73 -- Stardate: 4187.3
The shuttlecraft Copernicus lands on the planet Kzin to investigate statis boxes from
the extinct Slaver race; but the crew is captured by Kzinti raiders who hope to find a
super weapon in the statis boxes.
Beyond the Farthest Star
12/22/73 -- Stardate: 5521.3
Kirk and crew beam aboard a huge derelict starship from an insect race, and learn that
the ship's insect crew self-destructed rather than carry a still-living malevolent entity
to other worlds.
The Eye of the Beholder
01/05/74 -- Stardate: 5501.2
Beaming down to a planet to search for the crew of the missing ship Ariel, the
Enterprise crew is captured by a race of slug creatures and become part of a zoo
01/13/74 -- Stardate: 5683.1
Kirk and Spock join a party of aliens to search for and recover a priceless artifact,
the loss of which may cause a galactic holy war; but they soon learn that one of the party
is a saboteur.