Earth. The second half of the XXI century. Frederick Hallem, a rather ordinary young radiochemist, accidentally discovers that in a dusty flask with the label “Wolfram” suddenly some other substance appeared. Spectrometric analysis shows that it is a plutonium isotope that theoretically cannot exist, in addition, it turns out that the radioactivity of a substance is constantly increasing and it emits positrons that carry unusually high energy. Hallem offers the only possible hypothesis: if a substance that cannot exist according to the physical laws of our universe still exists, therefore, before it was in a parallel universe, where these laws are different. After some time, it becomes clear that the inhabitants of the parallel universe - paralyudis - consciously carry out the exchange of matter between universes, which can occur infinitely with the release of energy in both universes. Thus, the Earth receives a source of unusually cheap, safe and environmentally friendly energy, called the Electronic Pump, and Halle becomes the benefactor of mankind, who does not suspect that the bulk of both theoretical and practical work has been done by other scientists.

But after several decades, the young science historian Peter Lamont concludes that the operation of the Electronic Pump poses a tremendous threat to our universe. Just as the temperatures of two bodies equalize due to the second law of thermodynamics, the operation of the Electronic Pump leads to equalization of the properties of two universes, the main difference of which is the magnitude of the strong nuclear interactions: in our universe they are much weaker than in the parallel one, and their gradual increase ultimately should lead to the explosion of the Sun and our entire branch of the galaxy. Lamont rushes with his ideas from the Father of the Electronic Pump, who, in essence, throws him out the door, to senior officials, but no one wants to see what he does not want to see.

Then Lamont tries to make contact with the paralympics and convince them to stop the Pump. From the parauniverse several times pieces of foil came with symbols and drawings that could not be deciphered - the ways of thinking of earthlings and paralytes are too different. Myron Bronovsky, known for translating Etruscan inscriptions, helps Lamont. They send messages in the terrestrial language to the para-universe, hoping to find the key to paracharacters, and in the end Bronovsky receives the answer - the word “fear” written in clumsy earth letters, and soon after that two other messages from which it follows that the Pump really carries danger to itself, but the para-universe cannot stop it. Lamont, who already does not understand what is more important for him - to save humanity or simply to prove his innocence, to prove that the Father of the Electronic Pump is an inflated quantity, cannot use these messages as evidence - he will inevitably be accused of forgery. His only ally leaves the game, summing up everything that happens with a quote from Schiller: "Against stupidity, the gods themselves are powerless."

On one of the parauniverse planets, in a world that cannot be represented by humans, there are two types of living creatures - Rigid and Soft.

Rigid have a constant body shape, consisting of a dense substance, and an opaque shell. Soft tissues are very rarefied, the shape of the body is variable, they can flow, throw prominences, spread out and thicken - all this because they live in a world with a large amount of interatomic interaction, so the atoms that make up their body can be at a great distance from each other . Soft must certainly exist in triads, in which each of the components - rational, pestun and emotional - has certain qualities that ensure harmony and function of the triad. Rational (left-handed) - the bearer of intelligence, emotional (middle) - feelings, pestun (right-handed) - instinct of caring for offspring. Parts of the triad periodically enter a process called synthesis, in which their bodies are rarefied, matter is mixed, an exchange of energy and consciousness takes place. At the same time, all three become one, feelings and consciousness dissolve in the pure joy of being. The synthesis lasts many days, then each of the three again becomes itself. In some cases, during the synthesis, reproduction occurs - a kidney is tied. Each triad should give birth to three children, who almost do not differ from each other at an early age, but then acquire the properties of a rational, pestun and emotional. Matured children part with their parents (until this moment they are under the vigilant supervision of a pestun), and then combined into new triads. The triad ends its existence in the process, which is called the "transition".

Both Soft and Hard live in caves and feed, absorbing energy in the form of thermal radiation. Rigid, who have machines, appliances and libraries, teach rationals, and pestuns and emotions do not need training.

Unlike other Dua’s emotions, the middle of the triad of Una (rational) and Tritt (pestuna), knows how to really think, she’s interested in what emotions should not interest - this is even considered indecent. An unusually developed intuition helps her understand a lot that is inaccessible to the analytical mind of rationals. She learns from Un that the Pump, which gives energy to her world, threatens the death of another universe. But the Rigid ones are not going to stop the Pump, the planet does not have enough energy, and the Pump is dangerous only for the Earth, and for their world, the Pump’s work only leads to faster cooling of the already cooling sun. Dua cannot come to terms with this thought. She also hates the Hards because she comes to a terrible conclusion: Soft ones are just self-reproducing machines created by the Hard ones for fun, and the transition means death. It penetrates the Hard caves, elusive, because it can penetrate the stone, dissolve in its matter, and finds messages from the Earth. She is as incapable of deciphering them as the Tough ones, but she captures the emotions contained in the symbols. It is Dua that sends to Earth those messages that Lamont and Bronovsky receive. She almost dies from exhaustion, but she is saved, and then she finds out that she was mistaken - Soft ones are not machines, but the initial stage of development of Hard ones. The transition is the last synthesis, as a result of which the triune individual of the Tough is formed, and the more outstanding the components, the more an outstanding personality is obtained in the process of synthesis. Un, Tritt, and Dua are synthesized for the last time.

With a group of tourists, Ben Dennison flies to the moon, who once had high hopes as a scientist, but had the imprudence to speak dismissively about the future Father of the Electronic Pump, which doomed himself to obscurity. Like Lamont, he came to the thought of the danger of the Pump. Dennison flies to the moon, hoping to resume research in the field of paratheory. He meets Selena Lindstrom, who turns out to be not just a guide, but an intuition - a man with unusually developed intuition - who works together with the famous physicist Lunyan Neville. Selena gives ideas, and Neville develops them and keeps Selena's unique abilities secret, because she suffers from paranoia and is afraid of earthlings. Despite the fact that the lunar colony was formed relatively recently, there is some antagonism between the moon and the earth. The inhabitants of the moon have already formed a certain physical type, they are aging much more slowly than earthlings, whom they contemptuously call "countrymen." Most Lunyans have neither nostalgia nor reverence for their ancestral home and strive for complete independence from the Earth - because the Moon is able to fully provide itself with everything necessary. Dennison, with the help of Selena, begins experiments, the results of which save mankind from the danger looming over him, confirm the brilliant idea and at the same time rehabilitate the disgraced Lamont. The essence of Dennison’s idea is that there are countless universes, so among them it is easy to find one that is opposite in the properties of the para-universe. This anti-para-population should be what is called the “cosmic egg” with very weak nuclear interactions and incredible density. Dennison succeeds, by changing the mass of pimezons, to “drill a hole” into the cosmic-universe, from which a substance carrying energy that can be used immediately begins to seep out. And if the Earth begins to receive energy in a double way - with the help of the Electronic Pump and leaks from the cosmic universe, then the physical laws in the earth's universe will remain unchanged, they will change only in the parauniverse and cosmic universe. Moreover, this is not dangerous for either one, because paralyuds will receive energy from the Pump, compensating for the acceleration of cooling of their sun, and there can be no cosmic life.

So, humanity is overcoming another crisis. Peter Lamont is finally gaining well-deserved fame, Dennison is offered any place in any earthly university or institution, but he remains on the moon and accepts Selena's offer to become the father of her child.