Deductions Through Time

There's a book. Written by a genius; published Oct. 31st, 1892. The Adventures of Sherlock Holmes. What could be more thrilling? That's exactly what Clara thinks. Dragging the Eleventh with her, she meets the great Arthur Conan Doyle. So how's it possible that when they return to the present, the book of Sherlock Holmes is empty and the man himself lives? (BBC Sherlock/Who)