A newly married woman discovers a murdered intruder in her library after the man, rifling a safe, is fatally stabbed; she pockets a small locket and collapses when her husband returns. A detective and the coroner arrive to examine the scene, noting a small wound over the heart and puzzling evidence from the safe and room. The narrative follows the household’s shock and the ensuing investigation as clues, theories, and concealed motives emerge, linking domestic unease with methodical detection and gradually revealing the hidden connections and circumstances surrounding the death.