O Joe L. colocou isso em um comentário. A história é o conto de Isaac Asimov “Each an explorer” .
Naquela história, uma pequena tripulação de seres humanos que viajam pelo espaço encontra um planeta onde a população humanóide local parece geralmente pacífica e primitiva, mas agressivamente defende uma certa planta de cereais que eles cultivam em grandes quantidades. Os viajantes especulam que os humanóides têm uma religião primitiva, onde eles tratam essas plantas de maneira sagrada.
Eventualmente, eles percebem que a planta está telepaticamente escravizando os humanóides para cuidar das plantas. Quando saem do planeta, descobrem na nave espacial que as plantas têm controle sobre elas. Eles parecem ter tido uma fuga de sorte do planeta e tentam avisar a Terra. Mas como a torção final, é revelado que eles estão levando os esporos da planta para a Terra.
Smith laughed. “You know, you’re completely off base. If those plants really had us under control, why would they let us get away to warn the others?”
Chouns paused. “I don’t know.”
Smith’s good humor was restored. He said, “For a minute you had me going, I don’t mind telling you.”
Chouns rubbed his skull violently. Why were they let go? And for that matter, why did he feel this horrible urgency to warn Earth about a matter with which Earthmen would not come into contact for millennia perhaps?
He thought desperately and something came glimmering. He fumbled for it, but it drifted away. For a moment he thought desperately that it was as though the thought had been pushed away: but then that feeling, too, left.
He knew only that the ship had to remain at full thrust, that they had to hurry.