Spock must go to Vulcan in order to perform the Vulcan mating ritual.

The Enterprise encounters an alien who claims to be the greek god Apollo.

The Enterprise encounters an ancient Earth probe bent on the sterilization of all life.

Kirk and three of his officers are accidentally transported into a parallel ""mirror"" universe where violence, greed, and evil are commonplace.

Kirk attempts to assist a primitive people that are ruled over by a computer named Vaal.

The Enterprise must stop an ancient doomsday weapon that is capable of destroying entire worlds...and has already totalled one Constellation-class cruiser.

When a landing party disappears and one man is beamed up dead, Kirk and Spock investigate and meet a pair of aliens who seem capable of performing magic.

The Enterprise is taken over by a group of androids who are working for Kirk's old nemesis, Harry Mudd.

When their shuttle is diverted to a planetoid, Kirk meets one of the pioneers of space flight, Zefram Cochrane.

Spock meets his estranged father when the Enterprise escorts a group of ambassadors to a conference on the planet Babel.

Kirk, Spock, and McCoy land on a primitive planet to negotiate a mining treaty, but soon find themselves involved with intrigue and must flee with a pregnant woman into the surrounding mountains.

A landing party, including the command staff, are infected with a disease that causes rapid aging and senility.

The Enterprise must deal with a creature from Kirk's past that feeds on human blood.

A serial killer stalks a planet...and Scotty is the prime suspect.

Kirk must defuse a Klingon scheme to destroy a grain shipment...and cope with a seemingly benign creature known as a tribble, which reproduces at amazing speed.

Kirk, Chekov, and Uhura are kidnapped and forced to participate in a series of gladiatorial games.

The Enterprise travels to a planet suffering from cultural contamination from an earlier expedition - the inhabitants mimic the culture of 1930's gangland Chicago.

The Enterprise must destroy an enormous space amoeba before it reproduces and threatens known space.

Kirk becomes involved in an arms race when the Klingons equip a native people with superior weaponry.

The Enterprise discovers three discorporeal intelligences who seek their help in gaining physical bodies...but one of them has plans of his own.

The Enterprise seek out a historical researcher and discover he has contaminated a culture, rendering it into a near-duplicate of Nazi Germany.

The Enterprise's command crew must thwart an invasion by aliens from another galaxy who plan to conquer this one.

The Enterprise investigates the disappearance of another starship and discovers a planet where the inhabitants are immortal...and engaged in a strange parallel of Earth's Cold War period.

The Enterprise is used to test a new super-sophisticated computer, but it soon develops a mind of its own.

Stardate 4040.7: The S.S. Beagle, missing for six years, is found as debris near Planet IV of System 982. Kirk, Spock, and McCoy beam down to the planet to investigate and find a ragged group of fugitive slaves trying to stay hidden from the police. These ""sun worshippers"" distrust the landing party but soon discover that they are not a threat. Kirk informs them that he is looking for another group of strangers led by a man named Merik. Merikus is the First Citizen of the Empire, but Kirk is not sure if it is the same man. Pursuaded to help them find Merik and his crew, the leader of the fugitives sends Flavius, an ex-gladiator, to be their guide. The landing party, however, is soon captured and led into the city where they discover a civilization much like 20th century Earth, but culturally similar to ancient Rome. The landing party find Merik, now First Citizen Merikus, who six years ago abandoned his ship and beamed his crew down to the planet. Those who could adapt survived, and th

Stardate not given: The Enterprise is sent on a mission back to Earth in the year 1968 to discover details about how the planet survived the arms race. While in orbit, the ship intercepts a transporter beam from an unknown part of the galaxy and beams the space traveler aboard. Surprised by what has taken place, the man identifies himself as Gary Seven and claims to be a 20th Century Earthman raised on an unknown world and trained to prevent Earth from destroying itself. Kirk decides to verify Seven's story before releasing him, but Seven escapes and beams down to the planet below. Kirk and Spock follow him to New York City, and Seven meanwhile discovers that two of his fellow agents have been killed in a auto accident. Seven is forced to complete their mission himself which is to sabotage an orbital nuclear platform, just low enough in the atmosphere to scare Earth leaders into prohibiting additional nuclear space weapons. Just as Kirk and Spock arrive, Seven beams out of his office a