The clock struck midnight as the mansion's grand hall echoed with the sound of a distant, haunting melody playing softly. Detective Harper arrived at the scene, his trench coat flapping in the cold wind, eyes scanning for any suspicious activity nearby. A scream pierced the silence, sending shivers down the spines of the guests who had gathered for the lavish party. Lady Evelyn, the hostess, clutched her pearls tightly, her face pale as she pointed towards the darkened library door. The butler, Mr. Graves, hurried to her side, his expression grim, knowing that something terrible had just occurred inside. Detective Harper pushed open the heavy door, revealing a lifeless body sprawled on the floor, blood pooling around it. The guests gasped in horror, their whispers filling the room as Harper knelt to examine the victim's cold, lifeless face. A single, blood-stained letter lay beside the body, its cryptic message hinting at secrets long buried within the mansion's walls. Harper's mind raced, piecing together the clues, knowing that every second counted in solving this chilling, mysterious murder.