The clock struck midnight, echoing through the dimly lit mansion. Shadows danced across the walls, whispering secrets of the night. A chilling wind howled, rattling the ancient windowpanes with force. Detective Harper arrived, trench coat flapping, eyes scanning the eerie scene. The butler stood trembling, pointing towards the grand staircase's top. Blood stained the carpet, leading to a door slightly ajar. A scream pierced the silence, sending shivers down spines. The guests gathered, faces pale, murmuring in hushed, anxious tones. Harper approached the door, heart pounding, hand reaching for the handle. The mystery began, unraveling secrets hidden within the mansion's walls.