Fate of Worlds

Fate of Worlds: Return From the Ringworld is a science fiction novel by Larry Niven and Edward M. Lerner, published by Tor in 2012. It is the fifth book in the Fleet of Worlds sequence and also the closing volume of the Ringworld series, so it draws its cast from both halves of the story.

The novel opens decades after the events of the previous Fleet of Worlds book, at a point where the Ringworld has gone. That absence turns the Puppeteers from careful onlookers into a target, because rival war fleets move against the Fleet of Worlds once the technology everyone had come to rely on has vanished. The Hindmost, the puppeteer leader living in exile, is one of the few beings who understands what the Ringworld was and how it worked, and winning back his standing depends on how he uses that knowledge while his own kind are under attack.

Niven and Lerner write the book as a conclusion rather than a fresh start, and they lean on the shared history of the two sequences: puppeteer caution, human improvisation, and a very old galactic setting in which the disappearance of a single artefact turns immediately into a military problem.