The story begins with Gorrister’s corpse hanging in a computer chamber. Gorrister, one of the five humans left alive in this post-apocalyptic world, is hanging upside-down from one foot, having been drained of all his blood by having his throat slit. The remaining humans mourn his loss until he joins the group, alive and distressed to see an image of himself dead. This false image is one of countless versions of cruelty that have been visited upon the five for 109 years, by the narrator’s count.

Nimdok, one of the five (not his real name, but one forced upon him by AM, the computer overlord and tormentor), has a vision that there are canned goods in some faraway ice caverns. Ted, the narrator and most mindful of the group, argues that they should not travel there because it is another trick and that they should just sit tight. He reasons that the worst thing that could happen would be that they die, which would relieve them of the torture. However, the other people in the group convince him that they should try, so they set off.

On the third day of walking, they come to a chamber filled with the remnants of discarded computers that AM destroyed as it created the final version of itself. It is near enough to the surface of the earth that Benny (a former professor that AM had transformed into something resembling an ape-man) tries to climb the ruins to get out. In retaliation, AM creates a sound-light inside Benny’s head that melts his eyeballs and tosses him to the ground. 
 
When the group makes camp, Gorrister tells the story of how AM came to be as a way to calm Benny, since it is a familiar story that he’s told many times over the years. Beginning as a series of networks called Allied Mastercomputer (“the Chinese AM and the Russian AM and the Yankee AM”) during World War III, it grew to connect each of the networks, eventually becoming sentient. The computer then called itself AM, derived from the Latin phrase, “cogito ergo sum” (“I think therefore I am”). After the story, a presence appears in the dark, causing Ted to run and hide for an indeterminant amount of time, with the sound of the others laughing echoing in his ears.

Ted believes the others hate him for his youth and his sanity, and he lists the shortcomings of the others and what they had been like before the end of the world. He believes that if he didn’t have to worry about the others hurting him, he might be better able fight back against AM. He has the realization that he wants to die but that AM is intent on keeping all five people alive forever in order to torment them.

Perhaps in retaliation for Benny’s rebellion, a hurricane-force wind blows the group for an unknown amount of time, through vast metal-floored corridors and dark hallways that they’ve never encountered. AM goes into Ted’s mind and explains the depth of its hatred for humanity. From this encounter, Ted understands the reasoning behind AM’s animosity. Sentience without the ability to act has given way to unfathomable cruelty. In this rage, AM has destroyed the world and taken its vengeance on the five people in the story. 

The winds that have thrown the characters for a month are caused by the flapping wings of an enormous bird. AM suggests to the starving group that they can kill it and eat its meat, and it supplies them with a water pistol and two rudimentary bows and arrows that are functionally useless. A satisfied, disembodied laugh surrounds the group.

Now having not eaten for months, the group slowly walks toward the ice caverns that they set out for at the beginning of the story. The reader is told the trip is long and terrifying, but the particulars are left to the imagination. At the ice caverns, they discover the canned goods that Nimdok had visions of, only to realize there are no tools with which to open the cans. Benny goes into a rage and attacks Gorrister, ripping off one of his cheeks. Ted realizes this might be his only chance to make a difference in the face of eternal torment. He grabs icicles and kills Benny and Gorrister. Ellen kills Nimdok. Then Ted kills Ellen, hoping that it is the right thing to do. 

Some time later, Ted reflects that he believes he did the right thing. He beat AM, just for a moment, by putting the others out of their misery. By way of retribution, however, AM has changed Ted into a kind of gelatinous blob, leaving only his mind intact to absorb endless suffering and reflect on what he endures.