Kirk, Spock and McCoy enter a time portal and get stuck in the past on a planet about to be consumed by a nova

Kirk and Spock are forced into a battle of good and evil

Kirk is forced into negotiating peace on a planet with severe class inequities

A charismatic leader and his followers hijack the Enterprise in their search for "Eden"

Kirk and crew meet an immortal human named Flint

Zetarians threaten Lieutenant Mira Romaine

A deadly computer image protects a long dead outpost

Kirk is abducted by aliens who wish to use him to help solve their overpopulation problem

Two survivors of a devasted planet remain committed to destroying one another

Kirk is confronted by one of his heroes, now criminally insane

Kirk is distracted while the Enterprise is threatened

The landing party is used to test an empathic race

Hyperaccelerated aliens, invisible to the naked eye, take over the Enterprise

Platonians use psychokinetic power to toy with the crew

Kirk is trapped in interphase, while the Enterprise is trapped by a powerful energy web

An inhabited asteroid is on a collision course with a Federation planet

A malevolent entity pits Klingons against the Enterprise crew

As punishment for trespassing, Kirk and crew are forced to re-enact the shootout at the OK Corral

The sight of a Medusan ambassador causes insanity

A group of children are being controlled by an evil force

Kirk loses his memory and begins a life in a native village

Disguised as a Romulan, Kirk steals a cloaking device

Spock and McCoy are forced to fight in Roman-like games

Enterprise is used to test the new M-5 computer

The Enterprise finds a planet devasted by disease that appears to treat the American flag with great reverence

Extra-galactic beings commandeer the Enterprise in an attempt to return home

Enterprise is sent to planet Ekos to investigate a disappearance of Federation historian John Gill

Telepathic aliens take over Kirk and Spock's bodies

The Klingons provide arms to a peaceful planet and disrupt the balance of power

A giant space amoeba threatens the entire galaxy

Kirk investigates a planet with an Earth-like 1920s gangster culture.

Three disembodied beings wager on fights staged by prisoners abducted from around the galaxy

The Enterprise is overrun by furry creatures while tangling with Klingons and bureaucrats

Scotty is implicated in a Jack the Ripper-style murder

Kirk is determined to hunt down a vampiric entity he failed to destroy in his past

Accelerated aging affects the senior officers and threatens Kirk's ability to lead

The Enterprise crew becomes embroiled in a local power struggle on a tribal planet

Tensions run high when the Enterprise transports ambassadors to the Babel Conferences

The shuttlecraft Galileo makes a forced landing on a world with a single human inhabitant

A takeover leads Kirk to his old nemesis, Harry Mudd

Aliens on a mission of conquest hold the crew captive

A machine that destroys planets threatens the Enterprise

The crew discovers a paradise controlled by computer

Kirk, Scott, McCoy and Uhura enter a parallel universe

The Enterprise encounters a probe named Nomad

The Enterprise is held captive by the Greek god, Apollo

An alien being fights himself across two realities

Kirk and Spock battle Klingons to free Organia

An unknown monster threatens a mining operation

The Enterprise visits a colony where indigenous flower spores provide the settlers with peaceful contentment

The Enterprise is diverted by two planets fighting a computerized war

Kirk meets Khan, a leader of Earth's Eugenics War

The Enterprise crew finds a world run by a computer named Landru

Kirk is recalled for a potential court-martial

The Enterprise is thrown back to 20th century Earth

Kirk is pitted in a barehanded duel with a Gorn

A powerful entity known as Trelane torments the crew of the Enterprise

Seven Enterprise crew members go on a shuttle mission with Spock in command

On shore leave, the crew's thoughts come to life

After attacking an outpost, Romulans battle the Enterprise

Kirk suspects Shakespearean actor Anton Karidian as a mass murderer

Spock hijacks the Enterprise to return an injured Captain Pike to Talos IV

Spock hijacks the Enterprise to return an injured Captain Pike to Talos IV.

Kirk bluffs his way past what appears to be a powerful alien.

A new treatment for the criminally insane has deadly results

A strange group of children are discovered on an Earth-like planet

Nurse Chapel's long-lost fiancé is found — along with his androids

The Enterprise rescues con artist Harry Mudd and his "beautiful" female cargo.

A transporter malfunction creates an evil Kirk

The Enterprise crew catch a virus that removes their inhibitions

Kirk's friend, Gary Mitchell, is transformed into a god-like entity.

A powerful teenage boy wreaks havoc aboard the U.S.S. Enterprise