Although the story postulates a race of intelligent non-humans, it is set in the Foundation universe, during the era of Trantor's Galactic Empire.

The few remaining members of the only intelligent non-human alien race the Galactic Empire has discovered have been removed from their dying planet and transferred to the much more pleasant Cepheus-18 (hence their name, "Cepheids").

The scientists that study the Cepheids differ on whether to treat them as sentient beings or as animals, but agree that the aliens are in danger of extinction as they have ceased to reproduce.

While the administrator already suspects that this is due to a certain ennui, the Cepheids' leader later admits personally that while their race would likely have soon died out on its dangerous home world as their science only covered their biological needs; they have nothing to live for in a galaxy completely ruled by humans who provide for all their physical needs, and they are prohibited from leaving the Empire.

[2] The aliens' predicament in a human-dominated galaxy is similar to the eventual fate of humans in the alternative futures of The End of Eternity.