This is book four of a series of five books.
The existence of Ringworld is now known to all the species of Known Space. With such a prize, or threat on hand, everyone with an interest has sent ships to watch Ringworld, and also to watch the other watchers. A stand-off referred to as The Fringe War. The human military, the ARM, have developed a new antimatter weapon which is powerful enough to destroy Ringworld.
Louis Wu has been rejuvenated and is now young again. But he and The Hindmost are effectively prisoners of Tunesmith The Pak Protector he created to defeat Bram.
Louis is dragged along as Tunesmith works on his plans to repair centuries of damage under Bram’s rule, and also to deal with the threat of The Fringe War spreading to Ringworld.
But Louis’ main fear is what Tunesmith’s ultimate plans for him will be. He must find a way to free himself from this much more powerful and intelligent being before that time comes.