"Beyond the Wall" is a ghost story by American Civil War soldier, wit, and writer Ambrose Bierce.
The next morning, he discovered that the woman had been bedridden with illness and in her last night on earth demanded to have her bed moved to the other side so she could knock on the wall.
S. T. Joshi lists "Beyond the Wall" among a handful of Bierce's "simple tales of revenge in which the supernatural is a scarcely veiled metaphor for the conscience of the guilty".
[1] Some critics dismiss "Beyond the Wall" as a "lackluster and unimaginative" retread of Bierce's "spectacular" early story "The Middle Toe of the Right Foot" (1891).
[2] "Beyond the Wall" is notable for describing San Francisco as "a desolate, foggy, and mysterious" place, an image that would be popularized by noir fiction in the mid-20th century.