Deep in London’s Scotland Yard sits an evidence room dedicated to the greatest mysteries of British history. In this “Black Museum” sits a misshapen hunk of lead—two bullets fused together—the key to the untold story of a wartime encounter between Florence Nightingale, the mother of modern nursing, and a supernatural Man in Grey. The record books show Florence fought for compassion as empires’ petty rivalries threatened to destroy the hopes and lives of common people. But a guest in the Black Museum knows the truth is not so simple, and the famed Lady with the Lamp had a ghastly secret…