It is the twenty-third century, and humans have moved out into the Solar System. And not much further. 90% of humanity still lives on Earth, which the other 10% considers a noisy, crowded slum. The rest live in Settlements, in Earth or Solar orbit. One Settlement, Rotor, discovers there’s a nearby red dwarf they dub Nemesis. Rotor has had it with their crowded neighborhood and leaves.
Once at Nemesis, it’s discovered that Nemesis really is Earth’s nemesis. It will pass close enough to Earth in 5000 years to destroy it. That doesn’t matter to Commissioner Janus Pitt. Warning Earth would ruin his plans to build a new civilization, one not dependent on a silly planet where there would be weather and… Ew! Cultural diversity! Yuck!
Meanwhile, Earth and the Settlements figure out why Rotor left, and they learn that Nemesis will destroy Earth in five millenia’s time. One could forgive the remaining humans in the Solar System for being just a tad upset about that. They’re so upset that Earth reclaims its long-lost scientific lead to develop true FTL (or as Asimov calls it, superluminal) flight. They’re first mission? Go find Rotor and call them out on leaving everyone else to hang.
But this grandiose story doesn’t center on Pitt or Earth. It centers on Marlene Fisher, the daughter of the woman who discovers Rotor. Marlene has an odd ability to read body language. She’s so good at it that it’s impossible to lie to her. She leaves the Solar System as a toddler and spends most of her life drawn to Nemesis’ sole habitable planet, Erythro, which is actually a moon of brown dwarf/gas giant Megas.
Erythro has not been populated, partly because something there once caused a plague of mental instability, but mostly because Commissioner Pitt is obsessed with keeping Rotorians in space.
Meanwhile, back on Earth, Crile Fisher is obsessed with seeing his daughter once again. Sent to Rotor, where he became a citizen and married the astronomer who discovered Nemesis, he leaves before he ever learns why and where Rotor wants to leave. Forced to leave his family behind, Fisher eventually becomes attached to the first FTL project on Earth, seducing and later becoming the willing partner and confidant to the most qualified scientist to make it happen.
Asimov is not noted for his action, and his names sometimes are cringe-worthy. For instance, Marlene Fisher’s mother is named Eugenia Insigna, a name that does not exactly roll off the tongue. But an Asimov story is just serviceable enough to make the hard SF he excels at appealing and accessible. Eugenia is terrified her daughter’s ability will get her into trouble. She’s also frightened as Erythro begins to have bizarre effects on Marlene. Eugenia is a lioness, despite her daughter’s independence.
The story overall looks at some fascinating concepts, including one of the best theories of how faster-than-light might work, the implications of one group of people packing up and leaving humanity behind, and how Earth itself, like so many of the powers that have dominated it over the centuries, might fade from prominence.