The unnamed narrator of the story lives alone in a dark, ancient castle surrounded by a dense forest. He never sees sunlight, and he has no memory of human contact. One day, desperate to see the sun, the narrator decides to climb the ruined tower which is the only part of the castle taller than the trees. After the dangerous climb to the top room of the tower, the narrator is delighted to see the moon through a grating. Soon, however, he discovers the horrible truth behind his confinement.