Our walk through the Upper East Side made my bones ache and sweat pool in the small of my back but we weren't spotted, which was the main thing. The streets were deserted - presumably Gary had pulled all of the dead away from this area to join the ranks of his army. That didn't mean we took a lot of chances. We moved through the streets of Manhattan using a cover strategy that Jack called "bounding overwatch," which meant I would hide in a shadowy doorway, my eyes scanning a street corner while Jack crossed the open space as fast as he could. Then he would take up position behind some kind of cover and I would do what he had just done, though far more clumsily.

We saw a number of buildings that had been pulled down by brute force - presumably for the bricks that built Gary's tower. Hands and feet stuck out of the resulting rubble piles. Clearly Gary hadn't worried much about job site safety when he sent his troops out for building materials. We only saw one active dead man, which was just enough to give me heart palpitations. If Gary had been using his eyes at that moment we would have been screwed - and there was no way we would know, not until we got to the Park and found Gary waiting for us. Thinking about it made me want to panic, so I tried not thinking about it. Which didn't work.

The dead guy was standing in the middle of Madison Avenue, a stretch mostly bare of cars. He had his back to us, staring at a storefront covered up by a hoarding that had been turned into one giant billboard. COMING 2005: LA PERLA, the ad assured us. Beneath was a blow up of a woman wearing nothing but bra and panties, her back arched, her face turned to the camera with a look of disinterest. Even enlarged ten times her normal size her skin looked flawless, poreless.

His skin was discolored and blotchy, riddled with sores and sloughing away from wounds on his hands and his back. His head moved back and forth, his neck making a wet click every time. What could he possibly be looking for in the advertisement? Did he think the giant woman was some kind of food? I had never seen any evidence that the dead were interested in sex.

Jack and I waited for fifteen minutes behind the side of a building, waiting for the corpse to move on but it became apparent he wasn't going anywhere. Finally I looked over at Jack and took a combat knife from my pack. He nodded. I had intended to hand him the weapon but apparently it was my turn. He lifted a finger to his faceshield - be quiet about it, he was telling me.

I figured it was better to be fast. I ran up to the ghoul as fast as I could in my bulky suit, the knife held high so I could stab it right down into the top of his head. I stopped cold, though, when the dead man spun on one unsteady ankle and turned to face me head on. His eyes were so obscured with white sclera that his pupils were completely hidden. He must have been nearly blind. His jaw hung loose under his skin, unconnected to the rest of his skull. I had never seen a dead man in such lousy shape. Pity welled up inside of me but not before I had brought the knife down, skewering his head. He dropped to the pavement in an ungainly heap.

We reached the edge of Central Park less than an hour later. We scoped out the devastated landscape - dried mud, lots of it, and plenty of denuded trees which offered some cover. We could see a few of the dead milling around but they were far enough away not to spot us. We hoped. Jack led me into one of the transverses, the streets which run crosstown through the park. We headed down between the stone walls that turned the transverse into an artificial box canyon and soon we were up to our ankles in brown water. When the dead ate the grass and the plants of Central Park they removed the only thing standing between the manicured public gardens and erosion. The first good rain had turned Central Park into a series of arroyos, prone to flash flooding and the weathering effects of white water. Now the transverses were shallow rivers and the old water catch basins of the park - the ponds, the lakes, the Jacqueline Kennedy Onassis Reservoir - were reduced to oily puddles. It's impossible to walk silently through standing water but luckily we didn't have far to go. About a hundred and fifty feet into the transverse we came across a pair of tall iron gates set into the retaining wall. Beyond lay darkness - a lot of it.

Jack took his police lockpick out of his bulging pack. The lock on the gates looked simple enough but it took quite a bit of straining and twisting to get it open. At one point Jack took out a metal file and noisily scraped at the face of the lock. Perhaps it had rusted shut. I was busy keeping an eye out for the dead so I couldn't tell you. Finally the lock popped open with a clang and we were inside.

The tunnel beyond the gate had a sandy floor (now submerged under a few inches of water - I could see the sand at my feet, glittering here and there with flecks of mica, the sand erupting in billowing clouds every time I shifted my weight) and a vaulted ceiling of white brick. There were lights up there but they weren't working. A fine mist of water filled the air of the tunnel, obscuring visibility past about ten feet ahead of us. Our own shadows loomed before us in that mist, floating on vapor. Every movement I made seemed magnified, enlarged beyond all significance. The shadows multiplied as we moved into the darkness and snapped on chemical lights, their swirling shapes looming toward me or racing away on the reflections of our lights in the water. There could have been anything in that tunnel - an army of the dead could have been coming straight at us and we would never have known. The close walls and round ceiling of the tunnel seemed to stretch out, threatening at any moment to disappear and drop us into infinite darkness without warning.

Eventually we came to a room full of turbine equipment - long dormant, thankfully, or we would have been electrocuted. The big round machines lay in a row like eggs or sleeping forms between us and a wrought iron spiral staircase that lead upward into misty darkness. Our rubberized boots didn't clang so badly on the steps but the water that poured out of the folds of our suits as we ascended made for a sloshing, dripping, noisy climb. At the top of the staircase sat a room made of brick, containing only a few sticks of broken furniture and a stained mattress in one corner. There were windows but they showed nothing but sloppily-joined bricks. There was one door, a big locked steel fire door that was our next destination. Assuming it lead anywhere.

Gary had built his tower across a big patch of Central Park without, apparently, thinking much about what was in the way. He had torn down many of the park's buildings for bricks but others - those near the Great Lawn - had simply been incorporated whole into the structure. Belvedere Castle, one of my favorite places in New York City, had become little more than a buttress for one enormous curtain wall. On the uptown side of the tower the southern Reservoir gatehouse had found a similar purpose. It had been built right into the tower, something Jack had seen in the video product we took from the Predator. What Gary didn't know, we hoped, was that there was a tunnel leading from the south gatehouse to one of the transverses. The tunnel we had just come through.

It was possible that the door we faced now could have been sealed off during construction. It was also possible that it opened directly into Gary's personal apartments. Or into a guard room full of violent corpses. There was no way of knowing without trying it.

This was our plan, then. Ayaan would distract the dead - drawing as many of Gary's thousands of soldiers to her as she could, holding out as long as she might on top of the Museum of Natural History. Simultaneously Jack and I would break into Gary's fortress, kill any of the living dead we found inside (including Gary) and get the survivors to a place where Kreutzer could come pick them up in the Chinook. It was the best idea we'd come up with. I was committed to it, ready to give my life for its success. We both were.

Jack didn't waste any time. He grabbed the doorknob and turned. The door swung open on well-oiled hinges, revealing a dark brick-lined corridor beyond. None of the dead appeared out of nowhere to attack us. Dry air blew across us, blowing away all but a few tendrils of mist rising from the spiral staircase.

Jack shrugged out of his heavy pack and dropped it to the floor, then helped me do the same. He unzipped my pack and started drawing out long silver cylinders with nozzles on their ends, the kind you would use to store compressed gas.

I had never seen them before. "What are those?" I whispered, my voice sounding inaudible even to me inside my faceshield.

Jack looked up, his calm face framed perfectly by the square window of transparent plastic. "There's been a change of plan," he said.