The story of a medical doctor in the period of the American Civil War, a saga of the doctor's journey from his first posting in pre-war Louisiana to his death in Maryland in the 1870s, the novel revolves around a fanciful form of leprosy called Cain's Leprosy, including the discovery of its causes and the development of a treatment regimen. The under-nurtured Andrew, a quick study in things scientific, is a slow study in things human and barely knows how he feels about anything, particularly in his relationships with women.