And maybe that would have been the end at last, but yesterday, I saw Serena on the street. Though she was some distance away, I knew her instantly. I recognized the way she turned her head to look at things, the way the other pedestrians parted to let her pass. She wore a long black dress. Her hair was tied up. I’d never seen it that way before. It looked pretty on her. I crossed the street. I quickened my pace. She stepped sideways to avoid a small trash lake created by a dip in the concrete, the recent rain. You can learn a lot by watching people when they think they are alone, but in this city, everyone assumes a certain amount of observance. She gave nothing away. I followed her for eleven blocks, until she went into a small grocery and emerged with a fresh clutch of cut flowers. I followed her for three more, until she stopped to check her reflection in a large store window. She grimaced into the glass, smoothed her dress down her thighs. She was older, of course, like I am, but her face had lost none of its coercive quality. I wondered who had died, and if she had loved them.

“Excuse me,” I said. I had looked for her, of course. In the years following that summer, when everyone seemed to be findable online, I looked for her. There was nothing, not even a news story about the Center’s summer program, or about her disappearance, or about any of the schools and mental hospitals she’d supposedly attended or burned to the ground. I couldn’t find her parents’ names anywhere either. No address, no phone numbers. It was as though she had never existed.

She turned. “Yes?” she said. And was I, after all, sure that she had? I wasn’t sure of much anymore. Janet and Laurel had seen what I had seen. There was a time we would have all sworn to it. There was a time we would have sworn to a lot of things. But now, so many years later, would it be the same? Does it even matter who saw what? Does it even matter what happened, and to whom?

“What are you doing here?” I said. It mattered, it mattered. I had dreamed about her for years. She looked the same now as she did in my dreams. Exactly like her old self; nothing like her.

Something passed over her face. “You must have me confused with someone else,” she said. I saw that she was holding her purse tight against her body. The flower heads pointed at the pavement. Peonies.

“Those are lovely,” I said.

She stared down at them as if she’d forgotten what they were. “They serve a purpose,” she said. “There’s a difference.”

I took a step toward her. “Serena,” I said.

“That’s not my name,” she said. She hid the flowers behind her back.