Spock falls victim to the Vulcan mating drive, Pon Far, and must travel to his home planet to end his struggle -- in a death match with Captain Kirk.

The crew is held captive by a powerful being who manifests himself in the form of the Greek god Adonais -- and demands that the crew worship him.

The Enterprise crew encounters a 200-year-old Earth probe, believed to be responsible for the destruction of an entire star system -- and brings it on board the ship.

A transporter accident sends Kirk, Scott, Uhura and McCoy to an alternate dimension, where the unscrupulous crew advance in rank through assassination, and the Enterprise is poised to destroy a world.

The crew finds a seemingly peaceful world controlled by a super-computer, where the very environment around them reveals itself to be deadly.

The Enterprise faces an ancient planet killer that has entered our galaxy, and an unstable Federation commander tries to use the ship to stop it.

The Enterprise is threatened by a pair of aliens bent on conquest, who use a powerful device to instill terror in their victims.

The crew finds galactic scoundrel Harry Mudd on an unnamed planet, where a group of androids cater to his every whim.

Kirk and crew discover a legendary Federation scientist -- believed to be long-dead, but kept alive for centuries by a formless alien entity.

The Enterprise ferries a group of Federation diplomats to a peace conference, including Spock's father -- who falls deathly ill, forcing the Vulcan first officer to weigh the importance of his duty.

Kirk, Spock and McCoy arrive on an alien world to negotiate a mining treaty, but must protect the pregnant widow of the planet's murdered leader from a coup attempt. The Enterprise comes face-to-face with a Klingon war ship in orbit.

The crew of the Enterprise is stricken with an illness that causes rapid aging, incapacitating even the command staff -- and leaving the ship vulnerable to Romulan attack.

Captain Kirk defies orders to pursue a blood-sucking cloud creature he believes to be responsible for the deaths of half his crew 11 years ago.

Multiple murders lead to an investigation by the Enterprise crew, with all evidence pointing to Scotty as the perpetrator.

The Enterprise crew arrives on a space station to defend it from a possible Klingon attack -- but find that the biggest threat may come from a mass of gentle, furry creatures.

Kirk is forced to fight a group of alien prisoners in an arena, while those who enslave them -- and his crew -- gamble on the outcome.

The crew find a civilization that has modeled itself after mobsters of 1920's Earth, and Kirk and Spock must play their roles in order to end a lifestyle of constant violence.

The Enterprise encounters a giant space amoeba believed to be responsible for the destruction of a Federation starship -- and an entire solar system. Kirk must choose between Spock and McCoy for a suicide mission.

Kirk returns to a primitive, peaceful world he visited once before, only to discover that the Klingons have armed a tribe in conflict with his friend's.

The Enterprise picks up a group of disembodied aliens, who are allowed to assume the bodies of three of the crew in order to construct new forms of their own -- though they may not be willing to give them up.

The Enterprise investigates the disappearance of a Federation historian, and the crew discovers that the world he is on has shaped itself in the oppressive image of Nazi Germany.

The Enterprise is hijacked by a group of explorers from another galaxy, who intend to use the ship to make the long journey back home -- and turn most of the crew into small mineral blocks.

Kirk and Spock find themselves in the middle of a civil war, perpetuated by a rogue Federation captain.

The Enterprise is chosen to be the test ship for a new, highly-advanced computer -- which proceeds to take control of the vessel and lead it into a deadly war games scenario.

Kirk, Spock and McCoy are captured by a Romanesque civilization while investigating the destruction of a Federation ship, and are forced to fight in a gladiator arena for the local population's entertainment.

The Enterprise travels back to 20th century Earth, and finds a man from an alien world attempting to manipulate human history -- who claims to be preventing Earth from destroying itself.