A Creature of the Night by Fergus Hume

I did not get much sleep that night after the excitements of the day, but towards the morning fell into an uneasy slumber, during which I had fragmentary dreams in which Pallanza, the Contessa, and the antique chamber were all mixed up together. One moment I was at the iron door of the tomb, and the guardian angel took the semblance of Signora Morone; the next I was kneeling beside the corpse of Pallanza, illuminated by the faint light of the candles; and I ever saw the pallid shade of Donna Renata pointing towards the watchful face of her husband, filled with ghastly meanings in the dim shadows. No wonder, after these terrific visions which blended the real and the ideal, I awoke in the grey morning light unrefreshed and haggard; so when the waiter brought me my roll and coffee I left them untouched, and, lying quietly in bed, wondered what step it was necessary to take next in solving this riddle.

Riddle do I say? No! it was a riddle no longer, save as to the visit of the Contessa to the vault of her family, for otherwise everything was clear enough. She had met Pallanza at Rome, and had fallen in love with his handsome face. The young man, flattered by the attentions of a great lady, had yielded readily enough to the charm of the situation, but, growing tired of the intrigue, had come to Verona, where Bianca awaited him, with the intention of breaking it off. With a woman of Giulietta Morone's fiery nature the sequel can easily be guessed -- she had followed him hither, and having in some way forced him to come to the deserted palace, had there poisoned him out of revenge for his contemplated infidelity.