Spock travels back in time to prevent his death as a young Vulcan.

Cyrano Jones introduces tribbles that cannot reproduce.

Spock, Sulu, and Uhura discover a time capsule from an ancient and technologically advanced race. However, it draws some unwanted attention.

The Enterprise crew must work with Klingons to escape from a pocket universe.

The Enterprise finds a long-lost explorer.

The crew of the Enterprise races to find a way to stop a cloud from destroying inhabited planets.

Telepathic aliens put Kirk, Spock and McCoy in a zoo.

In orbit around a dead star, the Enterprise comes across a huge starship inhabited by a parasitic life form that threatens the entire ship.

The Enterprise crew begins to shrink after radiation exposure.

Female crew members must take over the Enterprise when the men are incapacitated by a race of sirens.

While exploring the planet Argo, Kirk and Spock are turned into water breathers.

Space con artist Harry Mudd returns, selling a fake love potion.

Kirk returns to the "shore leave" planet, but it's not as peaceful as it was when they last saw it.

Kirk and Spock are recruited for a heist to recover a stolen relic, which if not recovered could spark an galactic jihad.

A race of plant people, and their master, have a plan to force peace onto the galaxy.

At the center of the galaxy, the Enterprise discovers a race of powerful aliens.