A Victorian English scientist and gentleman inventor, identified by a narrator simply as the Time Traveller, lives in Richmond, Surrey.
He explains to his weekly dinner guests that time is a fourth dimension and demonstrates a tabletop model machine for travelling through it. He reveals he has built a machine capable of carrying a person through time. At dinner the following week, a weary, bedraggled Traveller stumbles into the room and recounts to his guests what he has experienced on his journey to the future.
In the new narrative, the Time Traveller tests his device. At first, he thinks nothing has happened but soon finds out he went five hours into the future. He continues forward and sees his house disappear and turn into a lush garden. The Traveller stops in A.D. 802,701, where he meets the Eloi, a society of small, elegant, childlike humanoids. They live in small communities within large and futuristic yet slowly deteriorating buildings and adhere to a fruit-based diet. His efforts to communicate with them are hampered by their lack of curiosity or discipline. They appear happy and carefree but fear the dark, particularly moonless nights. They give no response to mysterious nocturnal disappearances, possibly because the mere thought of it frightens them. After exploring the area around the Eloi's residences, the Traveller reaches the top of a hill overlooking what was once London and finds only the ruins of what had once been an impressive metropolis. He concludes that the entire planet has become a garden, with little trace of human society or engineering from the hundreds of thousands of years prior, and that communism[21] has at last been achieved. He also theorizes that intelligence springs from necessity; with no real challenges facing the Eloi, they have lost the spirit, intelligence, and physical fitness of humanity at its peak.
Returning to the site where he arrived, the Traveller is shocked to find his machine missing; it has been dragged by some unknown party into a nearby structure, resembling a sphinx, with heavy doors locked from the inside. Luckily, the machine cannot travel through time without its levers, which he had removed before leaving it. Later, he encounters the Morlocks, ape-like troglodytes who live in darkness underground and surface only at night. Deducing that this second race must have taken his time machine, he explores one of many "wells" that lead to the Morlocks' dwellings, where he discovers them operating the machinery and industry that makes the above-ground paradise of the Eloi possible. He alters his theory, speculating that the human race has diverged into two species: the favored aristocracy has become the intellectually degraded Eloi, and their mechanical servants have become the brutal, light-fearing Morlocks.
Before narrowly escaping the tunnels, the Traveller also observes the "underworlders" eating a strange meat, which he cannot at first identify. He later comes to the horrific realization that the Morlocks raise the Eloi like cattle and then use them as a food supply.
Meanwhile, he rescues an Eloi named Weena from drowning, as none of the other Eloi take any notice of her plight, and with time, they develop an affectionate relationship. He takes Weena with him on an expedition to "The Palace of Green Porcelain", a distant structure which turns out to be a derelict museum. Here, the Traveller finds a fresh supply of matches and fashions a crude weapon against Morlocks, whom he must fight to recover his machine. He plans to take Weena back to his own time. Because the long and tiring journey back to Weena's home is too much for them, they stop in the forest for the night. They are eventually attacked by Morlocks, and Weena faints. The Traveller escapes when a small fire he had left behind them to repel the Morlocks turns into a forest fire; Weena and the Morlocks are lost in the blaze, and the Traveller is devastated over his loss.
The Morlocks open the Sphinx and use the machine as bait to capture the Traveller, not understanding that he can use it to escape. He reattaches the levers before travelling further ahead to roughly 30 million years from his own time. There, he sees some of the last living things on a dying Earth: reddish, crab-like creatures slowly wandering the blood-red beaches chasing enormous butterflies, in a world covered in simple lichenoid vegetation. He continues to make jumps forward through time, seeing Earth's rotation gradually cease and the sun grow larger, redder, and dimmer, and the world falling silent and freezing as the last degenerate living things die out.
Overwhelmed, he returns to his own time, arriving at the laboratory just three hours after he originally left. He arrives late to his own dinner party, whereupon, after eating, the Traveller relates his adventures to his disbelieving visitors, producing as evidence two strange white flowers Weena had put in his pocket.
The original narrator relates that he returned to the Traveller's house the next day, finding him preparing for another journey and promising to return in a short time. After waiting for three years, however, the Narrator states that the Traveller has not returned from his journey.
