In traveling from Mozambique to Zimbabwe, Nhamo travels over Lake Cabora Bassa, a large lake with several islands in it. Nhamo stops at three of those islands on her journey. The first island at which she stays is little more than a large rock - thus, on the map of her journey it is called "The Rock". The island is surrounded by hippos, and Nhamo makes a camp there which she names "guinea-fowl camp", and teaches herself to swim.
Nhamo's time on "The Rock" is described in Chapter 14.