The recently unearthed diaries of the young Arthur Conan Doyle provide evidence, if not proof of the that Doyle knew Sherlock Holmes as early as 1878, when Holmes was working in the laboratory of Dr. Joseph Bell at the University of Edinburgh. Holmes, a brilliant scientist and an astute medical diagnostician had either dropped out or had been expelled from a London medical school.

This, the first diary, records the adventures of Doyle and Holmes, when they accompany Dr. Bell to Chicago. Dr. Bell gives lectures and demonstrates his surgical technique with Doyle's assistance. Holmes deduces the cause of death in a victim who collapsed on the street and Doyle becomes involved with the local medical students. Together, Doyle and Holmes uncover a plot by ex-confederate officers to assassinate the president and take over the United States.

The story demonstrates Holmes' amazing skills of observation, diagnosis, his ability to solve crimes and his dogged pursuit of criminals. During this adventure young Arthur Conan Doyle encounters his friend, Robert Louis Stevenson, is abducted by the James gang, falls in love with a red haired Scottish lass and survives a harrowing ride in a hot air balloon.