In Camus's short story, "The Guest," the desolate setting reflects the physical, moral, and emotional isolation of the protagonist, Daru.
When Balducci, the "gendarme," arrives on Daru's doorstep with the prisoner, Daru has immediate conflicts. For one thing, he feels no obligation to carry out orders for a task he has in no way asked for or is prepared professionally to carry out. But when he is told he has no choice, Daru is pulled in two directions.
First of all, he is European, not Arabian. Even though he speaks the language, has taught and fed the people, Daru has a sense that the gendarme's words may well be true. "If there's an uprising, no one is safe, we're all in the same boat," warns the gendarme. That is, Daru would immediately be relegated to the status of "other" if trouble arises.
Though unsettled by this revelation, Daru is conflicted. He feels a sense of obligation to a guest in his home, so integral to Arabian culture. The longer the prisoner is with him, the more strongly a "strange allegiance" develops between the two.
Ultimately, Daru makes the ultimate non-decision: he will neither take the man to prison nor help him to safety elsewhere. As the pair stand in the desolate landscape, the beginning of the story's isolated setting is echoed. Camus writes: "Daru surveyed the two directions. There was noting but the sky on the horizon. Not a man could be seen."
I think critic Paula Berggsen summed it up best. She argues that "both guest and host are obliged to shoulder the ambiguous, and potentially fatal, burden of freedom." Life, according to Camus, is a lonely, isolated battle and battlefield.