As with the Strecker Laboratory, there was no roof left covering this building. Although abandoned for the better part of century, its crumbling interior was clearly familiar to Shreve. Without hesitation, he led me through a maze of half-walled spaces that had once been patients' rooms.

Nan Rothschild had not exaggerated her description of howabruptly the city had abandoned these haunted properties. Old bedsteads were still in place, pairs of primitive crutches were scattered on the splintered floorboards, and glass-fronted cabinets with broken windowpanes held empty bottles on their dilapidated shelves. We had crossed through what I assumed had once been the formal central hall of the hospital and continued on to a room in the very corner of the building. For the first time in hours, the precipitation seemed to have stopped. I looked up and saw, instead, that someone had fashioned a makeshift ceiling out of a thin layer of plywood.

Shreve moved forward and my eyes followed the track made by his light. Here was an alcove that had been transformed into a sort of shelter in this outpost of exposed ruins. On the floor in the corner was a slim mattress from one of the old hospital beds. Not even two inches thick, the mattress had faded ticking that barely showed from decades of wear and exposure. A small table sat beneath the long stretch of open space that had once been a window, and assorted pieces of rubble had been carried in to prop up the boards overhead.

"Sit there," Shreve said, pointing to a wooden seat with a high back that had once been a wheelchair. He eased me onto the slats, which tilted backward and tottered as he knelt to retie my ankles. He stood behind me and reached around to place the handkerchief in my mouth again, tying it in back.

He walked out through the threshold of this small chamber and disappeared into the blackness of the adjacent rooms. What was he up to now? I wondered. Chills raced through my joints, my head still pounded, and my empty stomach ached and growled at me in the quiet of the very late night.

I stiffened my neck, shook off an array of grim thoughts, and pulled myself upright. Glancing out between the stone blocks, mitred at the top to form a pointed window frame, I could see from this direction the glitter of Manhattan's skyline muted by the endless flakes of falling snow. Straining my eyes, I could make out the spire of River House directly across the water from my corner seat.

Shreve must have made a call from his cell phone and left me alone so I would not overhear his conversation. But his voice echoed from within the thick gray walls of the neighboring area and I heard him ask for Detective Wallace. Why would hi anything about Mercer?

"Mr. Wallace? Winston Shreve here. Professor Shreve." Something about having just returned to his apartment and finding a message on his answering machine from Wallace. I had no idea what time it was now, whether it was still late Monday eve the early hours of Tuesday morning, the very last day of the year.

Of course, if I had been missing for any period of time, even Mercer would have been brought in from home in the effort to find me.

Shreve, in his most professorial manner, was telling him didn't mind repeating something he had told Detective Chapman earlier in the evening. "The two ladies got into my car in front of the school and I headed onto the West Side Highway to go up to Westchester. Sylvia was complaining of nausea and dizziness. We thought perhaps it was something she had eaten for lunch was making her sick. We'd just gone over that bridge into Riverdale when she sort of fainted, I guess you'd say."

Wallace must have asked a couple of questions and Shreve mumbled more answers that were inaudible to me. Flashbacks were coming to me now, just as drugged victims described emerged from the haze. I remembered being in the minivan and drinking the cocoa that the professor had bought for us.

"No, no. It was Ms. Cooper's idea. She suggested I get turn around. We drove immediately back to New York Presbyterian Hospital. Ms. Cooper knew where the emergency room was. Said she'd been there many times to see victims. I didn't waste time looking for a place to park, so she waited in and I carried Sylvia inside.

"Then when the doctor made the decision to admit her, I went back out to tell Ms. Cooper that I wasn't going to leave the hospital until I knew that Ms. Foote would be all right."

Wallace had questions. I rooted for him to break this goddamn alibi.

"Yes, Detective, Alex insisted on coming inside and waiting with me. I called the Lockhart house and told Skip's mother that we'd encountered a problem and wouldn't be able to keep the meeting after all. Alex came into the waiting room and-"

Shreve must have turned around and faced the other direction. It was more difficult to hear him but it sounded as though he was explaining how I'd passed the time while Sylvia was being treated by the medical team.

Whatever Shreve had drugged us with, I had no memory of the hours after the session in Sylvia's office broke up. It must have had amnesiac qualities. Is it possible that I actually had been inside the emergency room waiting area at New York Presbyterian? And if not, what a clever ruse. That place was a perpetual zoo. An endless procession of gunshot wounds, stabbings, car accidents, drug overdoses, women in labor, and miscellaneous misery of every sort. Most admissions were accompanied by strings of relatives and friends-whining, wheedling, bawling, and generally filling every inch of the enormous holding tank in which they waited for news of a loved one's condition.

The wind carried Shreve's words back to me. He must have shifted position again.

"For hours, Detective. She was there for hours. Watching television a bit, like everyone else. Making some phone calls."

Wallace was trying to figure out when I had left the hospital.

"Must have been close to nine o'clock. Yes, yes, of course. It was after they told us that Sylvia was awake and responding, but that they were going to keep her overnight for observation. I didn't want to leave without seeing her myself, but Ms. Cooper seemed impatient at that point. Told me she'd just grab a cab out on Broadway and get herself downtown."

Shreve hesitated before he threw in the next suggestion. "Seemed to be in a bad mood, Mr. Wallace. Something about a row with her boyfriend. Her beeper had been going off repeatedly and she paid it no attention. Rather willful, I'd say."

No one would argue with him on that point.

Shreve hadn't missed a detail. How stupid of me to have announced aloud to Mike that I had an unhappy boyfriend when my beeper had gone off at the beginning of the meeting in Sylvia's office.

"You mean come into the station house? Right now? But I've just told you everything that I know about-"

Break his balls, Mercer. Shreve'll never make it through a fact to-face encounter with you.

"Certainly, Mr. Wallace. No, no, thanks, I don't need a ride.'

Shreve's footsteps crunched again on the packed snow as r walked closer to my little sanctuary and bent his head to come in under the plywood covering. He ungagged me and stood in front of me to explain that he was going to leave for a short while.

"What did you give me to knock me out? What did you do to Sylvia?"

"You needn't worry. Nothing with long-term effects. Just sedative to make sure I could get you here and get her out of the way."

"A lot of a sedative. I can't remember anything."

Shreve smiled. "Gamma-hydroxybutyrate."

"GHB?" I knew it better than most. A colorless, odorless, tasteless designer drug, and I had quickly ingested it in my hot choc late in a matter of minutes. Most ironic of all is that it was making the rounds as a date-rape drug, being slipped into drinks of unsuspecting women to render them unconscious for several hours.