On a distant colony planet, a boy grows up wondering why the original colony ship departed many generations ago, at the same time scorching a road into the distance with its fusion drive. No knows where the road leads. The planet has a shortage of potassium and an upper class distributes what turns out to be potassium in exchange for their ruling status.
The ideas underlying the story are very clever. Unfortunately the story itself is confusing and hopelessly. I could barely finish the book. Given the neat premise, I wish Niven would have written an outline and contracted some other author to write the actual book.
Note: This is set in the same universe as The Legacy of Heorot and Beowulf’s Children, but there is no connection between the stories beyond that.