É o beco sem saída de Asimov. Não era tanto que as pessoas tivessem ido e vindo como ele tinha feito várias festas até o fim.
In the universe of the Galactic Empire (which would include eventually the Foundations), a non-human race is discovered and carefully herded to a planet to use as a combination zoo, laboratory, and reservation. Desperately unhappy, they are dying off, until the administrator in charge of their cage launches a clever plan to buy them escape and freedom. [Blurb from Jenkins' Guide]