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 automated Earth space probe Voyager One is approaching the Moon. With the radioactive exhaust from its engine certain to extinguish all life on Moonbase, the Alphans try to gain control and shut down the drive. Help comes when the probe's designer is found living on Alpha under an assumed name. However, Voyager is being followed by alien ships seeking revenge.

The travelling Moon drifts within range of a black sun. Pulled toward certain destruction by its inescapable gravitational force, the Alphans employ desperate measures to stay alive. As a lifeboat Eagle carries six persons to safety, the Moon plunges into the black sun, with only an experimental forcefield protecting Alpha.

After an encounter with a space-time anomaly, the Alphans find their Moon back in the Solar System on a course to re-enter Earth orbit. The celebration ends when it becomes apparent Earth is an inhospitable wasteland. The mystery deepens when they discover a duplicate Moon already in orbit and a duplicate Moonbase Alpha lying empty and deserted.

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.

The Moon approaches a solar system with two planets on opposites sides of its sun. The Alphans are trapped in an interplanetary conflict when warships from both worlds trespass on the Moon to fire missiles at their opponents' planets. After taking in a refugee from a destroyed gunship, the Alphans discover they have drifted into the middle of a literal war of the sexes.