It was midnight. He had left me here, in the basement, with instructions to finish the display before tomorrow’s opening. At The Mütter, my tasks were never-ending. Each piece required painstaking placement and anchoring invisible to the naked eye. I pushed my fists into my low back. Creaking and popping, I stretched, seeking to ease muscles stiffened by too many hours spent hunched at my table.

On the stairs leading to freedom, a familiar inky mist gathered and swirled. He always appeared...