To protect her daughter from the fast life and bad influences of London, her mother sent her to school in rural Ghana. The move was for the girl's own good, in her mother's mind, but for the daughter, the reality of being the new girl, the foreigner-among-your-own-people, was even worse than the idea.

During her time at school, she would learn that Ghana was much more complicated than her fellow ex-pats had ever told her, including how much a London-raised child takes something like water for granted. In Ghana, water "became a symbol of who had and who didn't, who believed in God and who...