The Prisoner of Heaven by Carlos Ruiz Zafón

The Prisoner of Heaven returns to the world of the Cemetery of Forgotten Books and the Sempere & Sons bookshop, where Daniel and his old friend Fermín Romero de Torres are tending shop. Daniel is now married with a son, and Fermín is soon to follow. Both men lead relatively happy and quiet lives. Enter an enigmatic visitor—a grim old man with a piercing gaze—who inquires about Fermín’s whereabouts. When told he is not in, the old man proceeds to buy the most expensive item in the store, a first edition of The Count of Monte Cristo; he adds a dedication and leaves it as a gift for Fermín. When Daniel reveals the details of this unsettling encounter to his friend, Fermín reads the dedication, turns pale, and at Daniel’s insistence, decides to open up about a past that has come back to haunt him . . . a story that will leave Daniel questioning his very existence.