"The Pit and the Pendulum" is a tale of the torture of a prisoner in Toledo, Spain, during the Inquisition. When the story opens, he has already been tortured so that he is "sick unto death with that long agony," and he is then sentenced to death. He remembers little from his "trial," then finds himself in a pit that's black as night. In exploring his dungeon, he discovers that it has a pit in its center.
He is occasionally given a pitcher of water and bread, and they drug him using the water. He awakes to find that he's on his back, bound to a board. He now has enough light to see, and soon notices a figure of Father Time on a panel of the ceiling, but instead of having a scythe, it has a pendulum, at the end of which is a giant, heavy ax, and the pendulum is descending with incredible slowness. Meanwhile, rats come out of the pit and go after his food. First, he tries to shoo them away, but then he notices that he is tied to the plank using the very material of his clothing, so he smears what's left of his meat on his clothing, lies very still, and waits for the rats to chew through it.
They do so only as the ax is level with his chest and bites into his flesh, but he manages to roll off the plank. He has hope now. He is "free" of the pendulum, but still in the clutches of the Inquisitors.
His hope is shattered when the pendulum is withdrawn and the eyes and figures on the walls light up with fire, and the walls begin to close in, forcing him to either be burned to death or to leap to his death in the pit.