“Well, that’s strange. She told me she picked the hotel on your recommendation.”

I got dressed again. I put on a navy blazer and black slacks, playing the role of hotel events manager. I made sure I was shaved, and I brushed my teeth and popped a few mints in my mouth to cover the smell of the bourbon. Then I headed to the elevators.

The hotel’s gold ballroom had a narrow second-story balcony that made a U around the palace-like space. From up there, people could lean on the elaborately carved railings and watch the wedding parties dance below them, or pretend that they were in powdered wigs and part of the court of Louis XIV. I let myself onto the walkway through a staff entrance and stayed discreetly at the back. No one was up here tonight. The action was below, in the darkened ballroom, with several hundred guests paying rapt attention to the woman illuminated on the stage.

Dr. Brier was dressed completely in black. Black pantsuit, black heels. In the stark spotlight, her head looked almost disconnected from her body, and her hands fluttered like flying birds as she gesticulated to the crowd. Her highlighted hair swirled as she walked from one side of the stage to the other. I could see the reflecting glint of her golden eyes like two faraway jewels. Her voice, through the microphone, had a mellifluous quality, the kind of singsong sweetness that could hypnotize you or seduce you, depending on what she wanted. It worked its magic. I didn’t think I’d ever heard our ballroom as drop-dead quiet as it was at that moment. Dr. Brier had these hundreds of people holding their breath.

“Think about what this means,” she told them, drawing out her words with a pregnant pause. “If we accept the Many Worlds theory as true, then our universe is constantly replicating itself, atom by atom, moment by moment, choice by choice. Every possible outcome of an event exists in its own separate world. We are all inching along on a single, solitary, fragile branch of a tree that grows infinitely larger with each nanosecond. As I leave the ballroom tonight, I turn left, but I also turn right. I go home, and I don’t go home. I kiss my husband, and I slap his face, and I have sex with him, and I stick a knife in his heart. In my consciousness, I only experience one of those outcomes, because I’m on one branch of the tree. But the Many Worlds theory tells us that all of those things happen in parallel universes.”

She paused. “Of course, I’m sure my husband is hoping I’m in bed with him later and not wiping the blood off my knife.”

Laughter rippled through the crowd.