Set fourteen years after The Integral Trees, the Citizen's Tree people discover that the data library from the original colony ship, Discipline, may still be intact. To find it they have to journey across the free-fall environment of the Smoke Ring to the Clump, a mass of debris. But Sharls David Kendy is still watching and waiting.

Only Jeffer, the Citizens Tree Scientist, remembers Kendy, the cyborg which had maintained Discipline's computer. He knows that Kendy will be as anxious as they are to obtain the library's information, and that a bitter struggle lies ahead of them all.