Bastei Lübbe #25012, ISBN 3-404-01054-X, 137 pages, 14 chapters, 38 lines/page

M. F. Thomas (or possibly M. S. Thomas - the cover credits differ from the internal credits) gives the readers not only the last book in the Mondstation 1999 set, but also the final adventure of the Alphans. Unlike Kurt Brand, Thomas has obviously read The Edge of the Infinite, as well as several of the other original German novels. This is indicated through the use of an Alpha Log recited by Dr. Russell as a prolog to the book (which also places Der Stahlplanet exactly one year after The Edge of the Infinite), by the use of Dave Reilly, by referencing Texas City and by using three of the characters from the other German novels. Thomas also has some familiarity with Space: 1999, using characters such as Bill and Annette Fraser, Yasko, Dr. Ben Vincent, and most unexpectedly, including a reference to Professor Bergman. Despite all of these touches, the novel is not very engaging and it contains a lot of filler - such as an extended sequence detailing Tony Verdeschi sneaking out of Command Center, stealing an Eagle and flying to the nuclear waste dumps, or inconsistencies - such as the machine entity's wildly varying power levels and capabilities. The story is a twist on The Infernal Machine, with the similarities being that a machine that lives in symbiosis with a living being has come to Alpha in search of the energy it needs to survive and an Alphan to use as a replacement corporeal body.

Most notable about the book is that it brings to a close the adventures of the Alphans. As the Steel Planet returns to its universe through a time rift, Moonbase Alpha is caught up in its energy wake, radically altering the Moons speed and trajectory. This shift in course eventually brings Alpha back into a line of communication, via neutrino transmission, with Texas City on Earth. The novel ends with the Alphans celebrating, knowing that their journey is finally over and that they'll all be returning to Earth. The last sentence has Koenig wondering if the Alphans will find the Earth so radically changed, that perhaps they will eventually want to return to Alpha. . .

As part of their never ending quest to improve their abilities to stay alive, the Alphans test a method of improving the range of the Eagles. This test involves simultaneously transmitting power from 4 Eagles over to the one requiring energy. Unfortunately for Carl Bellamy, the pilot of the Eagle that receives the energy beam, the experiment apparently goes awry and the Eagle is destroyed. An examination of Carl's retrieved dead body by Dr. Russell shows that all the energy, down to a subatomic level, has been drained from the corpse.

Shortly thereafter, a beam of light enters Command Center and begins playing across the equipment and computers, seeking out and probing for something specific. It then pauses before Maya, who with an odd smile on her face, walks into the beam and is dematerialized. Before Koenig and company can begin to understand what has occurred, massive moonquakes begin rocking the base. The quakes are centered around the nuclear waste stores on the far side of the Moon away from Alpha, and soon Koenig and Carter depart in an Eagle to investigate.

At the nuclear dump area, John and Alan find that several of the storage units have been ripped up and the canisters pulled out. However, the is no radiation. After turning around to head back to Alpha, the Eagle hits an unexpected forcefield. The Eagle barely survives the encounter and upon exiting the other side of the field a previously hidden spacecraft is revealed. It is a massive 20 Km diameter ship crafted out of steel and covered in weaponry. Its gravitational pull brings the Eagle down into a crash landing on the surface.

Koenig and Carter leave the wreckage and manage to find a passage into the ship. After some exploring, they come upon a tall silver skinned and haired alien named Number Nine. Number Nine reveals that he belongs to a group of defense spheres that were guarding a time rift between his universe and the Alphans, ready to battle any warlike creatures coming through the rift with ideas of conquest. By some accident, Number Nine and his ship were pulled through the rift and he has since been attempting to recover enough energy in order to return to his proper universe.

After completing the tale, Number Nine suddenly transforms into Maya. Back on Alpha, she had been taken over mentally and compelled to walk into the beam by Number Nine, who is actually a symbiotic computer/alien organism that required a new host body. She has finally been able to re-exert herself and take back control of her body. She then relates how Number Nine has plans to exterminate the Alphans - since they are a warlike species - but he doesn't have enough power yet to do so.