The morning unfurled in its ordinary way, sunlight poured through the Parsons atrium and turned the marble into a sheet of warm glass. People moved with practiced efficiency—coats straightened, shoes tapping, coffees clasped like tiny anchors. The office smelled faintly of lemon cleaner and ambition.

Down the east wing, in a part of the building that time had nearly forgotten, Julian and Serena had found themselves a hiding place. A narrow alcove behind a decorative screen, hedged by a ...