THE setting sun crawled through the vast windows of Oswald’s dressing room, a pale, reluctant light that made the gold fixtures glint like hidden knives. The room was quiet, save for the occasional rustle of fabric and the soft clicks of Nathan’s polished shoes against the marble floor as he moved around his boss.

Oswald stood in front of the tall antique mirror, tall and immovable, his shirt half-buttoned as Nathan fussed with the crisp cuffs and the perfectly pressed jacket that would go over it.

Nathan’s reflection caught Oswald’s eyes. The loyal aide’s brow was furrowed in that particular way that told Oswald exactly what was on his mind,...