The grandfather clock struck midnight when Detective Sarah Chen arrived at the old Victorian mansion on Blackwood Hill Road. Rain poured down in heavy sheets, obscuring her view of the imposing three-story house looming ahead through the darkness. She pulled her coat tighter and stepped out of the car, her boots splashing through deep puddles on gravel. A uniformed officer met her at the door, his young face pale and troubled beneath the flickering porch light above. Inside the grand foyer, a body lay sprawled across the marble floor, surrounded by shattered crystal from the chandelier. The victim was elderly, dressed in expensive evening wear, with a single gunshot wound visible on his chest nearby. Three people stood huddled in the adjacent parlor, their faces displaying various degrees of shock, grief, and something resembling fear. Sarah recognized the signs immediately; one of these trembling souls in this room tonight was almost certainly a cold killer.