When music-hall comedy duo Rolly Daconey and Irina Matei are threatened by a mysterious blackmailer, they turn to the Jekyll & Hyde detective agency for help. But the agency is experiencing turmoil and, unbeknownst to Muriel Carew, Henry Jekyll is ever more reliant on the elixir that transforms him into the brutish Edward Hyde. Still, there's nothing like a good case to clear the air, and the investigation soon points towards Lady Goodram's winter artists' retreat. But once Henry and Muriel arrive at Gaunt Manor, they're trapped by heavy snow, and they find themselves at the centre of a group of bickering performers, stage magicians and inventors whose long-standing rifts and petty grievances threaten to turn ugly. To make matters worse, a body is discovered – and the last person with whom the murder victim was seen alive was Edward Hyde. How can the detective agency get to the bottom of the case when their very presence puts everyone at risk? A thrilling locked-room mystery featuring the most unusual detectives in the business.