Rocket with a group of intergalactic explorers to the Ringworld, a massive artificial world looped like a giant ribbon the size of Earth's orbit around the sun.

Stranded on this bizarre world, they soon discover that what was once conceived as a Garden of Eden has now reverted to savagery. Civilization has disappeared, leaving powerful machines in charge. Vast ruins litter the surface where mighty floating cities fell from the sky, deadly plants use sunlight to kill, terrifying hurricanes the size of worlds swallow everything in their paths, while roaming gangs of native humanoids stand ready to attack.

Louis must now face the greatest challenge of his life. How can he and his friends possibly escape such a hostile place? What happened to the extraordinary treasures of this world? What kind of incredibly powerful alien could destroy the mightiest of the universe's worlds? And what happened to the legendary engineers who built the Ring? The answers lie in the conclusion to the most exciting, action-packed science fiction adventure ever conceived!