The pilot episode that introduces the main cast and sets the stage for the series. Located on the moon is Moonbase Alpha, a multinational scientific research facility. One of its duties is to also monitor and coordinate the activities surrounding two large lunar dumping sites where nuclear waste from Earth is disposed of. The Alphans are trying to launch a fast-tracked manned probe to an 'approaching' planet named Meta. The Meta Probe is in jeopardy since two of the mission crew have come down with a mysterious illness. The Alphans tie the illness to the nuclear waste about the time the smaller site unexpectedly explodes. While the Alphans try to avert a similar explosion in the larger waste site, it explodes also, and pushes the Moon out of the Earth's orbit, leaving the Alphans stranded on a moon destined to wander the universe. Written by James Rowings

A wandering energy force inhabits the body of Alpha technician Anton Zoref, turning him into an energy absorbing being.

After destroying an asteroid on a collision course with the moon, an even larger obstacle appears - an entire planet! On a recon mission, John Koenig encounters an inhabitant who convinces him- on the basis of faith- that the moon and the planet must collide. But no one else supports Koenig's stand. Written by Anonymous

Moonbase Alpha is attacked and devastated by warships from a nearby planet. With half of its population dead Alpha can no longer survive. Commander Koenig and Dr. Russel go to the alien world to plead for the survivors, but the inhabitants wish no one to disturb their serene existence. Written by Anonymous

On the ice world of Ultima Thule the Alphans encounter members of lost earth expedition who have achieved immortality- but at a price!

The Alphans encounter the Voyager space probe that has been wandering the cosmos propelled by the Queller drive- a faulty engine system. Following the probe is a fleet of alien ships from a world devastated by the drive.

The Alphans' joy turns to horror when the first child born on the Alpha matures into a five year old in a matter of hours. This is only a prelude to the arrival of formless alien fugitives- who plan to inhabit Alpha's population.

Discredited eagle pilot Tony Cellini is beset by recurring nightmares in which he was the only survivor of disastrous space mission. Now the moon is approaching the same set of circumstances that Cellini encountered.

The Alphans encounter a miles-long ark from the planet Daria, where the inhabitants have a very distinctive class separation.

The moon is approaching a black hole. Professor Bergman is a able to rig up an energy shield around the moonbase, but Commander Koenig feels this is only a desperate measure and has an eagle with six personnel dispatched as the rest of the moonbase await certain death. Written by Anonymous

Contact is made with the planet Piri, where the main computer created an idyllic life that led to extinction of its population through apathy. Now John Koenig must fight to save Alpha as his people fall under the same fate.

While exploring a cavern in an asteroid, the Alphans release Balor, a sadistic alien who has achieved immortality.

While returning from a reconnaissance mission to a nearby planet which appears to be capable of sustaining life, an Eagle team pass out and the ship is brought back under remote control. Upon arrival a passenger is found aboard the Eagle, who appears to be Dr. Helena Russell's husband, long presumed dead after a failed mission to Jupiter five years prior. The Moon Base Alpha crew must determine how this seemingly impossible situation occurred, all the while slowly drifting out of range of the planet which has offered the promise of a new home. Koenig must decide whether to go ahead with the evacuation to the planet before time runs out, but questions remain about the true nature of Dr. Russell's late husband, and whether the planet is truly safe. Written by Clay Daniel

A vessel of alien pacifists, bound for Earth, lands on the moon. They are greeted as friends by all- except Commissioner Simmons who sees their vessel as way to return home.

While exploring an Earth-type world several Alphans, including Commander Koenig and Dr. Russel, disappear after sighting a strange fog. Shortly afterwards a race of primitive humans are encountered.

An unknown space phenomenon seems to duplicate the moon (and everyone on it), then sends the doppelgänger into hyperspace. Everyone recovers except Regina Kesslann, who believes she's been living back home and is married to Alan Carter. In an astonishing coincidence, the Alphans discover the moon returning to Earth's solar system and Regina mysteriously dies when the moon re-enters the Earth's orbit. The Alphans are unable to contact anyone on Earth, which seems to have experienced an extinction event. Suddenly another moon appears in Earth's orbit which is discovered to be on a collision course with their own. A recon mission is assembled to find answers.

As the Alphans are planning to explore the planet Ariel, a 'missile' attaches itself to the en route Eagle. Upon returning to Alpha, the 'missile' gives the Alphans a lunar atmosphere. But the joy at the possibility of making a new world out of the Moon is short lived, as the moon does not enter orbit around the planet or its sun, and Alpha faces destruction from the newly acquired lunar air. Written by James Rowings

A visiting bizarrely-constructed alien ship sends out a friendly-sounding voice invites the team of Koenig, Helena, and Victor Bergman to enter the vessel. They have been communicating with the ship itself, which insists that the Alphans send out an eagle full of materials it needs for survival. The sole human entity aboard the ship informs the Alphans that he constructed the ship, which calls itself Gwent, and had infused it with his own personality. After the man (called Companion) dies, the Alphans realize the supplies aren't the only thing that the lonely Gwent has arrived here for.

Maintenance technician Fred Clifford is possessed by an eerie yellow glow, which ultimately kills him. It transpires that it is coming from a planet called Triton, which captures the Alphans and insists that Helena should become the Eyes of Triton. Before long she is acting just as Fred Clifford did before his death... Written by don @ minifie-1

After attempting to investigate a nearby planet, the reconnaissance Eagle goes haywire and crashes on the moon. Two of the crew were injured; Commander Koenig lay in a coma. Meanwhile, Koenig has been brought to the planet Zenno (which was not the planet they were investigating) to be studied by Raan, an alien anthropologist who considers mankind to be their missing link. Koenig is informed that his body on Alpha will soon perish and he will spend the remainder of his life on Zenno as a guest to be subjected to one psychological experiment after another.

Alien gyphs appear on all of Alpha's screens. Koenig sends an Eagle to investigate. The Eagle is lost and the pilot is taken over by a huge, alien 'Space Brain', using him as a channel to make the Alphans do its bidding. Koenig has to destroy it. Written by don @ minifie-1

Dan Mateo, one of Alpha's botanists, believes that he can increase their food supply by communicating telepathically with his plants. After passing out during one of his electronic experiments, Alpha seems to become haunted by a murderous and disfigured spirit. Written by don @ minifie-1

The Alphans land on the planet Arkadia, where glyphs suggest it is the cradle of civilisation from which life on Earth began. Now it is desolate and Koenig feels it is unsuitable for colonisation. Two renegade crew members have other ideas, however, and take Helena hostage in their demands to settle on Arkadia. Written by don @ minifie-1

The Alphans find themselves caught up in a long-running war between two rival planets, Betha and Delta. When a Bethan gunship, which has landed on the moon as a tactical advantage, appears to have been hit its commander Dione seeks sanctuary with the Alphans. Koenig attempts to negotiate a truce but Dione has other ideas... Written by don @ minifie-1