A mysterious shadow loomed over the dimly lit manor, as detective Larson arrived under a moonlit sky. Hering echoes resonated through the silent halls, carrying an unsettling promise. Looking around meticulously, Larson noticed an unusual pattern of footprints, leading towards the library. An ancient globe teetered dangerously at the far end, its position slightly askew. Studying the chamber, Larson found a solitary, crimson-stained letter, dated precisely one month prior. Peculiar death by a unique poison, he deduced, requiring extensive analysis. No signs of a struggle, causing the victims to demure softly, whispering cryptic fears. A stealthy escapade, hinting at a killer's scarcity, yet efficiency. The butler, a mere facade among many servile faces, seemed slightly too unnaturally still. An uncanny chill percolated the air, weaving an intricate web of intrigue. Detective Larson's sharp eyes locked onto a painting, slightly askew, teasing his curiosity. Behind the canvas, barely visible, a hidden safe cleverly concealed by painted facade. Inside, a vial, labeled "Arsenic," confirmed his suspicion of a deliberate toxin entry. The murderer's profile slowly crystallizing, Larson knew this puzzle required every ounce of his wit. Begrudgingly, the shadows seemed to lean back, as if observing the scene unfold. Night’s breath whispered secrets, and Larson was ready to listen intently, piecing together the enigma's foundation.