First, we hear about the invention of the Electron Pump – a source of limitless energy that transforms life for those on Earth. However, the discovery was not by chance – the invention was only possible with the collaboration of aliens in a parallel universe, with consequences for both universes due to conservation of energy, matter and momentum. The discovery would not even have been made without the personal animosity between two scientists, Hallam (who becomes known as the Father of the Electron Pump) and Denison (the more talented of the two, whose career never recovers). Years later, some scientists discover that the impact on our own universe could be significantly worse and more immediate than originally thought, but it’s heresy to question the wisdom of the pump and their opposition is dismissed.
Second, the story is told from the viewpoint of the aliens. The imagination and storytelling are superb. Asimov describes a totally different familial and societal structure to our own, focussing on the lives of a “Soft” triad and their side of the Electron Pump invention. The triad are Odeen (the Rational), Dua (the Emotional) and Tritt (the Parental). Each has a well-defined role in society – Odeen learns, Tritt bears the children and Dua should socialise with the other Emotionals, absorbing energy from the Sun. Dua is unusual, fighting against the norms of society and yearning to learn instead of sunning herself. Odeen is the top intellect of his generation – and Tritt, too, has far more invention about him than most Parentals. Together, they have huge potential and carry the hopes of the “Hard ones” who tutor the younger generation.
Third, we experience the story from a base on the moon, where Denison migrates in hope of reviving his career. He makes friends with a tourist guide, Selene, who was born on the moon and introduces him to the culture there. As Denison’s research matures, Selene becomes his assistant – they investigate the possibility of a new technique that could counteract the effects of the Electron Pump. Yet, again, Denison finds himself caught in a battle of wits with another scientist, Selene’s boyfriend, who has other plans for the research.