The Moon is on a collision course with an enormous planet. On a scouting mission, Koenig encounters Arra, the Queen of Atheria. The aged monarch proclaims the collision is a preordained event and must occur for her people to evolve to a higher plane of existence. Now Koenig must convince his staff to have faith and do nothing in the face of apparent destruction.

The Alphans celebrate the arrival of the first child born on the Moon. The blessed event sours when the infant grows into a five-year-old child in minutes. Trying to accept him, the Alphans do not notice that little Jackie Crawford is much more than he seems. When hostile spaceships approach the base, Koenig realises, too late, that the aliens have an agent on Alpha.

Encountering a derelict spaceship, the Alphans respond to an automated distress signal. On board, they discover what remains of the once-great civilisation of Daria: an elite group which maintains control of the ship and a tribe which has descended into savagery. The Alphans are appalled when they discover what measures the Darians have taken to survive.

While exploring an asteroid, the Alphans injure an alien trapped within. Bringing him to Alpha, they discover his wounds have completely healed. The indestructible Balor is a scientist whose people had discovered the secret of immortality. Balor is a psychopath, offering a drastic solution to his people's apathy; now freed of the eternal prison, he plans to spend eternity practicing the art of pain and torture, with the Alphans as his subjects.

A technician falls under an alien influence, accessing classified information before mysteriously dying. Soon after, the Moon is stopped in space by the powerful rays of an alien spacecraft. The aliens' only interest in Alpha is the data held in its computers, information they now plan to obtain through the possessed eyes of their next agent: Helena Russell.

John Koenig finds himself trapped on the planet Zenno, in the home of an alien scientist and his daughter. Advanced two million years beyond Earthmen, the aliens consider Koenig their missing link. Faced with the threat of being treated like an experimental animal for the rest of his life, Koenig uses an unexpected weapon to confound his captor: love.

Dan Mateo, hoping to unlock the secret of communication with plants, unleashes a killing force from the depths of his own mind. This macabre spectre seeks vengeance for Mateo's horrible death—which has not yet occurred. Bridging the span between science and the supernatural, the Alphans hope to break the cycle and exorcise the ghost without killing the man.

With Maya now a crew member the Alphans discover a young couple called Cantor and Zova who have been in suspended animation for some while. They claim that they are exiles from the planet Golos, following an invasion, and ask for the help of Alphan crew members to restore the planet to them. Helena and Tony accompany them to the planet Golos, where it is apparent that they are not the young innocents they appeared to be.

The Alpha Moonbase needs a rare ore known as Milgonite, which is detected on an extremely dry planet. Koenig leads a small landing force and discovers a glowing rock formation which comes alive and cuts off the party's links with the base. It is a trap - the planet needs water to survive and has lured the travellers there for the water in their bodies.