The story revolves around a mysterious cryptogram that holds the key to a hidden treasure. The protagonist, a young man named Harold, discovers the cryptogram in an old book and becomes obsessed with deciphering it. As he delves deeper into the mystery, he uncovers a series of strange events and murders connected to the cryptogram. With the help of his friend, a detective, Harold must navigate a complex web of clues and suspects to uncover the truth behind the cryptogram and claim the treasure before it falls into the wrong hands.
By Fergus Hume · First published 1904 · Genre: Mystery, Crime, Thriller · 26 chapters