Saul Williams wakes to another quiet morning on Mars, and laments being so far from Earth. He wants nothing more than to be home, but he knows that, because he has “blood rust,” this is impossible. He tries to imagine himself once again in New York City, yet his efforts prove futile.
Saul wants to die but lacks the nerve to kill himself. Instead, he naps, and awakens with a mouth full of blood; “blood rust” is terminal and incurable, causing its victims to die over the course of a year. Those suffering have all been quarantined on Mars.
Desperate for intellectual stimulation, a lonely Saul attempts to strike up a conversation about ancient philosophers with a man lying on a filthy blanket. The man is too sick for social interaction, however, and tells Saul that he, too, will soon not care about anything other than sleep. Saul looks out across the bottom of the dead Martian sea, where many other sick men are sleeping alone. Saul remembers that, upon first arriving, they had all huddled around campfires and talked about their intense longing for Earth.
Just then, a rocket lands on the dead sea floor. A man emerges, accompanied by two figures in protective suits. After setting up a tent for the man, the figures re-board the rocket and leave. Saul runs to meet the newcomer, who looks young and relatively healthy. The man introduces himself as Leonard Mark. Saul asks Mark how things are in New York City, and suddenly the city itself seems to erupt all around him. At first Saul is confused and terrified, but as the city fades and the desolate Martian landscape returns, he realizes that Mark had somehow created the vision in Saul’s mind. Saul joyously grabs Mark’s hand and expresses how happy he is that Mark has come.
Mark later tells Saul that he was born with his telepathic abilities, likely because his mother was pregnant during the 1957 “blowup” of London. His visions affect all the senses at once, and at Saul’s request, Mark makes him believe he is swimming in a beloved creek near his childhood hometown. So delighted is Saul after this that he attempts to pay Mark with his last bar of chocolate, but Mark refuses to accept it; he grants his visions solely because they make people happy.
Saul eagerly imagines all the places Mark will take him, as well as all the long-dead philosophers he’ll be able to talk to. Such imaginative possibilities, Saul thinks, are even better than being healthy back on Earth. His musings are interrupted, however, by the realization that that other sick men have noticed Mark and are slowly walking toward them. Saul tells Mark they must head to the mountains, insisting that the others are insane and will kill each other, or even Mark, in order to “own” Mark and his abilities. Mark coolly responds that he doesn’t belong to anyone, including Saul, and refuses to leave. Angry and desperate to keep Mark for himself, Saul smashes at the visitor’s chin, knocking him out, and then carries him to a cave in the mountains.
Later, Mark awakens tied up in the cave and calls Saul a man driven crazy by loneliness. Saul says he will untie Mark only if he promises not to leave, but Mark again insists that he is a free man and belongs to no one. He adds that he had been perfectly willing to share his talents among all the men, but Saul, in his greed, has ruined everything.
Soon enough, five other men reach the cave. They argue ferociously though the night, each determined to keep Mark—“their treasure”—for themselves. Determined to settle things, Mark proposes a schedule in which each man gets an hour with him per week, while Mark is also allotted plenty of time for himself.
Though at first the men appear to agree, one of them, Johnson, proposes that they instead force Mark to perform for them whenever they want and torture him if he refuses. To this Mark responds that Johnson is crazy, and that he’ll simply kill the others one by one. In fact, none of the men can trust the others not to murder them. What’s more, Mark adds, one of the men has a gun.
At this news, the men all jump up, and a chaotic tussle ensues. Johnson pulls the gun from his jacket and begins shooting wildly. Mark screams at him to stop and begins to conjure New York City around them. Saul tackles Johnson to the ground, at which point the image of New York begins to collapse. The men turn to see Mark standing with a bloody hole in his chest and then toppling to the ground, dead.
As the cave grows cold, the men begin to bury Mark. Saul, extremely weak, lies on the ground and attempts to conjure New York in his mind, but it’s no use. It is gone forever, he realizes, and cries himself to sleep.