The opening scene establishes the setting in Laburnam Villa, a small, out-of-the-way place, away from any big city. The stormy weather is threatening, but inside the Whites' cottage, the scene is cozy and safe with a brightly burning fire. Danger, therefore, lurks outside. Father and son are playing chess; Mr. White is willing to take risks in the way he plays the game, but we discover that after he had "seen a fatal mistake after it was too late, was amiably desirous of preventing his son from seeing it." This statement foreshadows later events in the story because Mr. White's recklessness causes consequences he doesn't expect.
The banging of the gate signals the arrival of their guest, Sgt.-Major Morris, a mysterious man who introduces the dangerous monkey's paw into the previously safe White house on a proverbial "dark and stormy night."
The first part of the story, which is the exposition, therefore, provides an introduction to the characters, establishes the setting, and provides some background information.