The TT notices that, in the confusion of his fight with the Morlocks, he accidentally sent himself into the future, rather than the past. Though he speeds up through time, the alternation of day and night slows down, as does the passage of the sun. Finally, the sun dully ceases to rise and set, and the earth rests with one side facing it, much as one side of the moon faces the earth. The TT slowly reverses the Time Machine until it stops. He observes the reddish landscape and the moss-like vegetation everywhere. There is no wind, and the water of the sea barely moves. The TT has difficulty breathing and believes the air is more rarefied than normal.
He spots a large white creature flying away, and then sees a huge, crab-like thing crawling toward him. Another one comes up behind him and touches him with its antennae. The TT quickly pulls his machine's lever and watches more of the giant crabs crawl along the beach as he shoots forward through time. The environment keeps up its deathly appearances as the sun grows larger and duller. After thirty million years, all life save the green vegetation ceases to exist, and it starts to snow. An eclipse turns everything completely dark. After the sun becomes visible again, the TT stops the machine. He feels sick and confused and "incapable of facing the return journey." He sees a black creature crawl out from the sea, and his fear of remaining in this environment compels him to climb back into the Time Machine.
With the TT's journey into the decaying, dying future, Wells suggests that entropy, the gradual dissipation of energy within an increasingly chaotic system, is the fate of the universe (for a fuller discussion of entropy, see the analysis for Chapter I). It makes sense that Wells would believe this, since entropy seems at odds with evolution--evolution implies that life becomes more complex and fitter with time, whereas entropy leads to chaos and death. As he has already shown with the Eloi and Morlocks, evolution leads to dystopian imperfection, not utopian perfection, and should not be considered as a vision of progression. Moreover, this dystopia is governed by entropy; the Eloi have little energy, physical or mental, and they live in chaotic fear of the Morlocks.
The TT's ideas are turned upside-down, and it makes sense that at the end of his journey he sees a life-form crawling out from sea. Just as life began in the water, so does it end. However, the universe no longer has the resources of the sun and the earth's movement to reproduce life, so the TT's adventure ends on a highly pessimistic note.
The TT relates to the men his travel back to the present time. The one difference he found was that his machine landed in a different corner of his laboratory, since it was moved by the Morlocks. Then, after gaining his bearings, he found the party having dinner.
He says he does not expect the men to believe him, but tells them to take it as a fictional story, and asks what they think of it. The men are quiet, and the Editor implies he does not believe the story. The Medical Man asks where the TT got the withered white flowers he has put upon the table; the TT insists that Weena put them in his pocket. The TT leads the men to the Time Machine, now slightly damaged and dirty. He says goodbye to his guests.
The narrator stays up at night thinking about the TT's story, unsure if it is true. He goes to the laboratory the next day and touches the Time Machine's lever. The machine shakes. He asks the TT if his story was true. He promises it was, and says he will prove it in half an hour when he's done working on the machine. He leaves, and the narrator realizes he has to meet someone soon. As he goes into the laboratory to tell the TT, there is a gust of wind and some odd sounds, and neither the TT nor the Time Machine is present. When a servant tells him he has not seen the TT outside, the narrator understands he has traveled into time again. He waits for him a while longer, but even three years later, the TT has yet to return to the present.
When the TT asks the men to take his tale as a fictional version of humanity's fate, Wells's makes a similar plea to the reader. He does not want his reader to view "The Time Machine" as a mere entertainment, but as a serious projection of the future, one plausibly backed by social and scientific arguments. That none of the TT's guests (save the narrator) will believe him suggests not that they merely find the idea too fantastic, but that they are unwilling to believe such a future awaits for them. As members of the ruling class, they do not heed the TT's warning of a class revolution. Instead, they remain concerned with the immediate future--when the cabs stop running, for instance--and not with preventing the dystopia the TT has described.
Wells removes the pessimistic tone Chapter XI ended on by allowing the TT to travel again through time, and with ambiguous results. That he chooses not to return to the present says something about his change in attitude. Obviously, time travel is an exciting, seductive lifestyle, and continuing adventures would be difficult to pass up. But maybe the TT understands that he no longer belongs with the Victorian elite, and sees in them the beginnings of the lazy, effete Eloi. Perhaps he has even dedicated himself to preventing the class-divided dystopia he originally saw (and saving Weena, too).
The narrator wonders if the TT went into the past or the future, and where his adventures may have taken him. While the TT believed mankind's progress turned out to be destructive, the narrator believes human civilization may still do some good as it matures. The narrator also chooses to view the future as largely unknown. He now owns the two white flowers from the future--proof, he says, that "even when mind and strength had gone, gratitude and a mutual tenderness still lived on in the heart of man."
The epilogue is a humanistic wrap-up to a decidedly inhuman story. Wells urges his readers to remember what ultimately bonds man--not his mind, but his heart--and as such may be his final plea for the Victorians to look at their own society and the class divisions that tear it apart.
The narrator also expresses optimism for the future though he knows what is in store for man. This is another upbeat note that suggests humans still have free will to change the course of their lives. Wells again encourages his audience to act, and not let entropy dissipate whatever energy they have to change the future.