What is the mood of The Cask Amontillado by Edgar Allan Poe?

The mood of The Cask of Amontillado by Edgar Allan Poe is dark, ominous, and foreboding. The narrator, Montresor, is consumed by his desire for revenge against Fortunato, and his plan to lure Fortunato to his death is carefully and methodically executed. The story is full of symbolism, with the catacombs representing the underworld and the Amontillado representing Montresor's poison. The overall mood is one of dread and suspense, as the reader is drawn into Montresor's twisted plot and waits to see what will happen to Fortunato.