Scottish missionary Frederick Arnot, 22, arrives in Shoshong (Botswana) with a goal of converting Africans and whites alike. Because other missionaries have been active there, Tswana King Kama has already converted to Christianity. Looking for new peoples to convert, Arnot will travel for three months northward into Barotseland (Zambia). He will be befriended by Litunga (king) Lewanika, who will keep him as his guest for a year and a half, to advise him on an alliance with Britain. When rebellion breaks out, Arnot will be sent away for his safety by Lewanika. He will travels further into the highlands, and happen upon the source of the Zambezi River.