The story follows Richard Digby, a stern, self-righteous recluse who withdraws into a remote cave to escape what he deems a sinful world while his heart is said to be literally calcifying. A devoted woman from his past travels to find him, offering a healing remedy and entreating him to rejoin community, but he refuses. The narrative traces his increasing moral and physical hardening, the woman's patient but failing attempts to reach him, and the symbolic consequences of isolation, fanaticism, and emotional sterility as the cave, the characters, and their fates become intertwined with images of stone and cold.