Rain hasn’t let up all night, and neither has the phone. When it finally rings past midnight, it’s Inspector Hale, and his voice has that particular flatness that means someone’s dead. Ashworth Manor. Come now.

You find Lord Ashworth slumped over his study desk, a shattered brandy glass at his elbow and no sign anyone forced their way in. Hale’s already pinned a scrap of corkboard to the wall — a tangle of string leading nowhere, evidence of a trail he couldn’t follow. “I know who was in this house tonight,” he says, “I just can’t prove who left last.” He hands you the thread. The rest is yours to trace.