World at the End of Time follows the story of a young Earth-born human, Viktor Sorricaine, on a colony expedition to a distant star system.

Unknown to both the humans of Earth and the colonists, the stars around them are home to immensely long-lived (effectively immortal) plasma creatures—with no knowledge of, or interest in, the activities of insignificant matter creatures.

After a disastrous disease outbreak and terraforming failures, the desperate colonists eventually decide to investigate the strange radiation emissions from a small world within their solar system.

The star around which the colony's world orbits has dimmed considerably (owing to the energy being siphoned off to accelerate it) and they are now travelling so fast that, because of relativistic effects, the universe around them has shrunk to a bright dot.

After the vast amount of time that has passed, all that remains of the once young universe are dead stars and black holes, with Wan-To desperately surviving on the energy provided by proton decay.