This historical novel tells two biographical stories side by side and then brings them together in an unexpected way late in the book. Arthur is Sir Arthur Conan Doyle, physician and writer, known especially for his Sherlock Holmes stories. His story starts with his childhood in Edinburgh and his closeness to his mother (Mam). His father is described as a gentle failure of a man.

After an early education by Jesuits in England and Austria Doyle studied medicine at Edinburgh University. After graduation he worked as a Locum-tenens, went to sea and eventually started a general practice in Southsea, England. He first became interested in Spiritualism at that time and was also writing stories. Sherlock Holmes provided him with sudden fame and he withdrew from practice, which had not been very successful.

His wife developed tuberculosis and was chronically ill for many years before her death, during which time he met and became emotionally involved with Jean Leckie who became his second wife and shared his belief in Spiritualism.

The second story is about George Edalji, the half-Indian son of a midlands vicar, who became a lawyer and was prey to a series of pranks and false accusations. He was falsely imprisoned and the two men meet when Arthur offered to try to help George seek retribution for this unjust event. Arthur's approach to the problem was "sherlockovian" but also real and at least partially successful. The interaction is fascinating as are the very different life stories of the two men and their families-real family drama.