Ringworld's children: Explorer Louis Wu, an Earth-born human who was part of the first expedition to Ringworld, becomes enmeshed in interplanetary and interspecies intrigue as war and a powerful new weapon threaten to tear the Ringworld apart forever. Now, the future of Ringworld lies in the actions of its children: Tunesmith, the Ghoul protector; Acolyte, the exiled son of Speaker-to-Animals; and Wembleth, a strange Ringworld native with a mysterious past.Fleet of worlds: It is two hundred years before the discovery of the Ringworld. Humanity has been faithfully serving the Citizens for years, and Kirsten Quinn-Kovacks is among the best and the brightest of humans. When a chain reaction of supernovae at the galaxy's core unleashes a wave of lethal radiation that will sterilize the galaxy, the Citizens flee, taking their planets, the Fleet of Worlds, with them. Someone must scout ahead, and Kirsten and her crew eagerly volunteer.