These twelve mysteries by the author of ‘The Scarlet Pimpernel’ concern a mysterious armchair detective who solves crimes from reports and using logic. The stories describe murders, blackmail, theft and deception, but all have as their setting the fog-cloaked Edwardian streets: Fenchurch Street, Percy Street and Lisson Grove in London. Dublin, Glasgow, and Liverpool are also home to cases that have baffled detectives.