The plot unfolds over a couple of centuries and begins with the sea adventures of a young radio operator embarked on a merchant ship in the 60s. During one of his travels, the young man meets a strange character who intrigues him and brings him closer to a mysterious supranational organization, the Phoenix, which aims to unify the planet under a single government that offers all the peoples of the Earth the sharing of peace and well-being. The young man joined with enthusiasm and, within a few years, reached the highest levels of the organization. Reached its purpose, the Phoenix begins the exploration of space
A courageous commander of the space forces meets, on an unknown planet, incorporeal beings who ask him for help to counter a cruel and bloodthirsty alien species that hinders their mission of peace in the universe. Later, the commander discovers that it was the Incorporeals who created the Phoenix on Earth in order to enlist the help of humans in their mission. The Earth forces defeat the enemy aliens and bring back the peace demanded by the Incorporeal who, later disappear without ever manifesting themselves to humans.
Space travel continues with discoveries of other planets and encounters with other species when, by chance, a Gate is discovered that allows to reach other planets, even millions of light years away, instantly. Continuing the research, we discover other Great Gates that allow travel also in time, as well as in space. Commander Gordon goes in search of the Incorporeal from which he demands an answer.
To restore peace to the universe he was forced to impose it by force and sacrifice countless lives of alien beings. After events make him suspicious of incorporeals, he goes after them to make sure he's fighting for a good cause. The search is led by scientists who formulate shocking new hypotheses about the creation of the universe.
Science and theology will take on completely different and unexpected meanings, when these theories will prove to adhere to reality and will allow humans to discover many mysteries of the cosmos that have always afflicted, frightened or intrigued all living beings.

Excerpt

During the first explorations with the Gates, an exploration sphere was sent to an unknown planet that orbits the star So-102, almost in the center of the Milky Way galaxy. The sphere exiting the Gate had found itself in a huge underground chamber that had housed the temporary bodies of the Incorporeal. At the time the interest of the Terrestrians was focused on other objectives but Gordon decided that now was the time to explore that planet. The question that arose was: why had they, or rather had, chosen that planet? In that part of the galaxy there was a lot of dark matter and possibly a black hole. Was there any connection between the two facts? He gave orders to prepare five Rangers with a crew of five Immortals and a battle sphere on each. He assigned command of the mission to Malcolm MacLeòid with One, embedded in a combat sphere, in command of the other spheres. Once the rules of engagement had been defined, the Rangers disappeared, one by one, into the toroid. The duration of the mission had not been established and Malcom would have decided it on the basis of the situation that he would have found on the planet. According to mission procedures, some exploration spheres would have stopped near the Gate, remaining interconnected with the entire squad, ready to report back in case of an emergency.

The five Rangers, having emerged from the toroid, found themselves in a large underground chamber along which walls were lined with numerous seats used by the host bodies and were all empty, as the exploratory sphere had found them on its previous visit. Malcom gave the order to analyze the atmosphere of the environment which turned out to be non-breathable for a human, as it was composed of a dense mixture of ammonia and silane58, but not harmful to the Immortals, who did not need to breathe. The temperature, which was within the bearable range, was -22°F. The Scotsman got out of the air-craft together with two of his, followed by One, who would not have stayed on board even if they had chained him to a bulkhead. Malcolm knew the Investigator's temper well, but paid no attention to it, since he was aware of its operational skills and knew that they could prove to be very useful. He also brought down the other combat spheres and ordered One to explore the chamber with them in search of an exit, while he and the other Immortals looked around curiously. Approaching the command machines of the Gate he noticed that, in addition to the usual four, not far away, there was a fifth machine, completely different from the others, which had the shape of a thin cylindrical column.
A member of his crew, a science officer, began to examine it carefully. It didn't take him long to discover that, placing a hand on the small column, a hologram appeared reproducing the black marble wall, which was about fifty yards away, in front of the Gate. In the hologram there was a luminous rectangle delimiting a large area of the image that reproduced the wall. The science officer tried to put his hand inside the rectangle and, to everyone's surprise, a part of the wall began to slide slowly to the side, revealing a night sky full of stars. When the mechanism stopped, it cleared an opening so large that the five Rangers could have come out side by side. They all got back on board and set off for that unexpected exit. Once outside, they rose to three thousand feet of altitude to observe the planet's surface. They found themselves above an expanse of desert which, in the light of the Rangers' powerful headlights, seemed to be undulated by rounded grayish sand mounds. The darkness was softened by the light of  the star, reflected from a large satellite that appeared high in the sky, almost at the zenith and there were no signs of artificial lights in any direction. Malcolm raised a Ranger at sixty thousand feet and when it descended again, the pilot reported that they were near the north pole of the planet.
He therefore decided to head south at low altitude to identify any signs of life. As they proceeded, at low speed, towards the equator the landscape began to change. The ground had more accentuated hills, partially covered by dark spots, formed by something that looked like low vegetation, of a dark gray color, similar to lichens. Near the equator the hills had become towering rocky mountains, with their sharp peaks rising from deep, dark gorges. The satellite had dropped far below the horizon, while So-102 emerged from the opposite direction, starting to illuminate the planet's surface and making the darkness of the starry sky fade. Malcom chose a plateau surrounded by high peaks and descended with his Ranger escorted by two others, while the remaining two air-craft remained motionless, suspended vertically from their point of descent. He got off the air-craft and had the atmosphere analyzed again. The science officer confirmed the mixture of ammonia and silane and told him the temperature was 50°F. An uninhabitable planet for humans, he thought, but not for their artificial bodies. The extraordinary materials that Marvin had created to cover the bodies were not affected in the least by the ammonia present in the atmosphere.
He walked, followed by his, towards the edge of the plateau, where a dark gorge began. Each Ranger's pilot and one crew member remained aboard, as per safety regulations. They had reached the gorge when, from one of the aircraft suspended above them, they warned that they had detected movements in another gorge that opened between the mountains on their right, a few hundred yards away. Malcolm asked the air-craft watch officer:
"What kind of movements did you detect? Could they be associated with life forms?"
 The officer replied immediately but in an uncertain tone:
"Commander, from the movements they seem to be living beings but I cannot detect any life form similar to the one we know."
Malcolm remained thoughtful for a few minutes and called the officer back:
 "Try to extend the analysis to any life forms other than human."
He paused for a moment and thinking of the host bodies of the Incorporeal, he resumed:
"They could be life forms based on silicon instead of carbon. Check it out."
After about ten minutes, the officer called him back:
"Commander you was right, they are living beings based on silicon. They are slowly approaching the plateau and, if they maintain their current travel speed, you should see them emerge from the gorge to your right within ten minutes."
They all returned to the Rangers, standing by the aft embarkation door. Not having the slightest idea of what intentions those unknown beings had, Malcolm released two exploration spheres and sent them, into the darkness of the gorge, to see what they looked like. Obviously, together with the spheres, One also came out and stood beside him. After a few minutes, the spheres returned and sent a record of what they had seen in the gorge over Malcolm's communicator. The beings were two, at least seven feet tall and they advanced slowly in the dark, moving on six very long, very thin limbs, which made them look like gigantic arachnids. From the front part of the small ovoid body, suspended on those very long legs, came out two other limbs, shorter, equipped with claws. On a protuberance of the body, which appeared to be the head, were positioned two large convex eyes without lids which, probably, were multiple vision compound eyes. Malcolm thought their appearance would not be very pleasant for a human, especially one with arachnophobia, who would see them as gigantic terrifying spiders.
The two arachneiform aliens advanced across the plateau and stopped about a thirty yards from the Terrestrians. They didn't seem to have hostile intentions, in fact they seemed just curious. One approached about ten yards from them to attempt a mental analysis, while the two remained stationary, inclining their bodies forward, towards the sphere, as if to observe it carefully. The voice of One was heard echoing in the silence of the plateau:
"Commander, they have rather simple minds but I am not receiving hostile signals, they are very curious. I try to get them to talk."
He began to emit a range of sounds from the lowest frequencies to those at the limit of hearing. After repeating the series of sounds about ten times, he noticed that when he emitted them at a very high frequency, just below the audible threshold, one of the two aliens emitted a similar faint sound. One tried to increase the frequency of the signals encroaching on ultrasound and he noticed that they responded with similar and much more intense signals. After several exchanges of sounds incomprehensible to both, the Investigator communicated to Malcolm:
"They have a language on an ultrasonic frequency but it doesn't seem easy to create a translator. May I put our language into his mind?"
Having received the positive answer, he moved within a yard of the two aliens, who remained still but bent their front paws even more, curious to look at the sphere. He mentally transmitted to them a pleasant sensation of relaxation and, after sensing that their minds were responding to his stimuli, he began a basic notional treatment that would enable them to communicate, even if in an elementary way, in the language of the Terrestrians. At the end of the treatment, the two aliens began to articulate sounds at a very high frequency which gave a shrill tone to the words, but quite understandable. Malcolm and his Immortals cautiously approached the two beings and the first sentence they heard was:
"Did you come get us?"
Everyone was amazed at the question, only One immediately realized that aliens had mistaken for one of the spheres of the Incorporeals. Malcom also noticed that and addressed the aliens, spelling the words well:
"We come from Earth, a very distant planet at the edge of the galaxy. We have no hostile intentions, we are here to explore your planet without harming any living being."
The alien immediately answered him with his shrill voice at the limit of hearing:
"There are only a few left… most of us left with spheres… like this one. They don't speak with a voice...they get inside our heads."
And pointed to One with a claw. Malcolm never expected such a situation. The Incorporeal had harvested the minds of most of the planet's inhabitants and was most likely not done yet. He left to One, the task of finding out where the black spheres were, who with oral questions and mental investigations managed to fulfill his task very well. Malcolm felt compassion for those monstrous but peaceful beings and before leaving them he warned them:
"The black spheres are your enemies and have killed your people. Avoid all contact with them and do not follow their advice. Stay hidden."
They took off from the plateau under the curious gaze of the two aliens who returned to the dark gorge, after seeing the five Rangers disappear in the clearing sky. The directions, One had received, weren't very accurate. The two aliens had mentioned the Great Encounter Space, probably a large plateau along the rocky equatorial belt, where their fellows gathered to meet the black spheres. The Rangers, spaced a few miles apart, began to fly over the equator at low altitude, just above the sharp peaks of the mountains. After several hours of flight, the first Ranger saw a large plateau below them immersed in the mountain range. They stopped above the vast level space where several hundred arachneiforms had gathered in the center. A line of individuals branched off from the large group and ended in a large opening in the side of the mountain. They were all slowly entering that cave. Malcolm ordered all Rangers to land in a corner of the large clearing and to disembark all combat spheres. His Ranger remained on the ground along with two others, while the remaining two flew up and remained stationary above the group of arachneiforms. Some of them noticed the Terrestrians' air-crafts but none interrupted their path towards the cave.
Malcolm got off the air-craft together with his agents and stood still watching the procession of aliens who, regardless of them, continued their slow journey. He gave orders to One with his spheres, to explore the cave where, most likely, they would find the black spheres of the Incorporeal. The order was to destroy them and nothing could have made One happier. At the command of four other spheres similar to him, he joined the column and set off for the entrance to the cave. The aliens took them for the spheres of the Incorporeal and promptly dodged to let them pass.
They walked along a long tunnel alongside the aliens, who were advancing slowly towards their destination, without arousing the slightest reaction in them. The gallery took them to a huge chamber crowded with arachneiform beings and, after a quick inspection, One noticed that there were many black spheres along the walls while, in the center of the chamber, on a kind of circular stage, there ware beings similar to those found on Upsilon B Andromedae by Gordon, with their monstrous bodies feeding on gamma rays. One decided to act immediately and ordered the other spheres to rise from the ground and fire. While they were shooting down the spheres and those monstrous bodies that were trying to escape by running towards the side galleries that branched off from the great main chamber, One felt an attempt to intrude into his mind and immediately activated his mental protection. He called Malcolm asking for the explo755 ration spheres to hunt down the fugitives and decided to try his new mental weapon that Sean had provided him. He was sure that the mind trying to creep into him was that of the Incorporeal still present in the remaining black spheres and he lowered his defenses slightly to initiate a very brief mind meld with him.
Within a fraction of a second, he was able to insert the deadly haunting rhyme and immediately raised his protection. For a few seconds he had an intense and almost unbearable sensation of a ferocious anger mixed with hatred and then nothing. The combat spheres and the exploration spheres had brought down a hundred monstrous bodies and fifty black spheres, under the amazed eyes of the arachneiforms, who did not understand what was happening. One approached an individual taller than the others and chose him hoping he was a leader or at least an individual who could convince his fellows. He instilled in him a feeling of calm and relaxation and gave him a basic notional treatment to allow him to communicate in the language of the Terrestrians. Soon after he called Malcom informing him that the mission was accomplished. When the group of Immortals entered the large chamber, the arachneiforms moved aside to let them pass and stood watching them, curious. One climbed onto the circular rise and noticed in the center of the structure a well, a couple of yards wide, at the bottom of which he saw massed inanimate arachneiform bodies.
After absorbing their minds, the Incorporeal thus cast off their bodies. Malcolm also climbed up and addressed the individual whom One had mentally treated:
"Tell your fellows that you have been deceived. They promised you a reward but they brought you death. These beings that enter your head are our enemies and yours too."
The being listened to him in silence but shortly afterwards he too went up and looked for a long time into the well where the bodies of his similar ones had been piled up. He turned to Malcolm and with a shrill noise he said simply:
"Thank you!"
They all got out and walked towards the gallery that led to the exit. When they were in the open, One approached what seemed to be a leader and asked him:
"Are there other gathering places like this?"
The arachneiform was surprised to hear a voice coming from the sphere, because he was used to receiving only mental messages from them and replied:
"This is the last remaining meeting place. All the others, unfortunately, have already completed their horrible mission…"
To One the phrase had no effect, but Malcolm sensed a deep sadness in that answer. Immediately afterwards he told himself that it was impossible to understand anything from those shrill sounds and he thought no more about it. There were still subtle differences between human and artificial minds. A few hours later, the five Rangers returned to the Gate, after having carefully closed the movable wall.