The water lapped higher again. It seemed to be rising in distinct surges. It had taken two full hours of frantic work to unlock all the doors, and as they were finishing, a roar louder than before overwhelmed them, and a dirty debris-filled surge poured over the whole park. Something upstream must have given way all at once. Any animals remaining in the lower section of the park would be swept away or drowned in place. Quickly the humans remaining drove the few big cats and polar bears they had herded into their trucks out the entrance and onto Connecticut Avenue. Now all Northwest was the zoo.

The truck that had delivered the Swimming Tigers of Khembalung headed north on Connecticut, containing the tigers in back and the Khembali delegation piled into its cab. They drove very slowly and cautiously through the empty, dark, watery streets. The looming clouds made it look like it was already evening.

The Swimming Tigers banged around in back as they drove. They sounded scared and angry, perhaps feeling that this had all happened before already. They did not seem to want to be in the back of the truck, and roared in a way that caused the humans in the cab to hunch forward unhappily. It sounded like the tigers were taking it out on each other; big bodies crashed into the walls, and the roars and growls grew angrier.

The Khembali passengers advised the driver and zookeeper. They nodded and continued north on Connecticut. Any big dip would make a road impassably flooded, but Connecticut ran steadily uphill to the northwest. Then Bradley Lane allowed the driver to get most of the way west to Wisconsin. When a dip stopped him, he retreated and worked his way farther north, following streets without dips, until they made it to Wisconsin Avenue, now something like a wide smooth stream, flowing hard south, but at a depth of only six inches. They crept along against this flow until they could make an illegal left onto Woodson, and thus around the corner, into the driveway of a small house backed by a big apartment complex.

In the dark air the Khembalis got out, knocked on the kitchen door. A woman appeared, and after a brief conversation, disappeared.

Soon afterward, if anyone in the apartment complex had looked out of their window, they would have seen a curious sight: a group of men, some in maroon robes, others in National Park khakis, coaxing a tiger out of the back of a truck. It was wearing a collar to which three leashes were attached. When it was out the men quickly closed the truck door. The oldest man stood before the tiger, hand upraised. He took up one of the leashes, led the wet beast across the driveway to steps leading down to an open cellar door. Rain fell as the tiger stopped on the steps and looked around. The old man spoke urgently to it. From the house’s kitchen window over them, two little faces stared out round-eyed. For a moment nothing seemed to move but the rain. Then the tiger ducked in the door.

SOMETIME DURING that second night the rain stopped, and though dawn of the third morning arrived sodden and gray, the clouds scattered as the day progressed, flying north at speed. By nine the sun blazed down between big puffball clouds onto the flooded city. The air was breezy and unsettled.

Charlie had again spent this second night in the office, and when he woke he looked out the window hoping that conditions would have eased enough for him to be able to attempt getting home. The phones were still down, although e-mails from Anna had kept him informed and reassured at least until the previous evening’s news about the arrival of the Khembalis, which had caused him some alarm, not just because of the tiger in the basement, but because of their interest in Joe. He had not expressed any of this in his e-mail replies, of course. But he most definitely wanted to get home.

Helicopters and blimps had already taken to the air in great numbers. Now all the TV channels in the world could reveal the extent of the flood from on high. Much of downtown Washington, D.C., remained awash. A giant shallow lake occupied precisely the most famous and public parts of the city; it looked like someone had decided to expand the Mall’s reflecting pool beyond all reason. The rivers and streams that converged on this larger tidal basin were still in spate, which kept the new lake topped up. In the washed sunlight the flat expanse of water was the color of caffe latte, with foam.

Standing in the lake, of course, were hundreds of buildings-become-islands, and a few real islands, and even some freeway viaducts, now acting as bridges over the Anacostia Valley. The Potomac continued to pour through the west edge of the lake, overspilling its banks both upstream and down, whenever lowlands flanked it. Its surface was studded with floating junk which moved slower the farther downstream it got. Apparently the ebb tides had only begun to draw this vast bolus of water out to sea.

As the morning wore on, more and more boats appeared. The TV shots from the air made it look like some kind of regatta the Mall as water festival, like something out of Ming China. Many people were out on makeshift craft that did not look at all seaworthy. Police boats on patrol were even beginning to ask people who were not doing rescue work to leave, one report said, though clearly they were not having much of an impact. The situation was still so new that the law had not yet fully asserted itself. Motorboats zipped about, leaving beige wakes behind. Rowers rowed, paddlers paddled, kayakers kayaked, swimmers swam; some people were even out in the blue foot-pedaled boats that had once been confined to the Tidal Basin, pedaling around the Mall in majestic ministeamboat style.

Although these images from the Mall dominated the media, some channels carried other news from around the region. Hospitals were filled. The two days of the storm had killed many people, no one knew how many; and there had been many rescues as well. In the first part of the third morning, the TV helicopters often interrupted their overviews to pluck people from rooftops. Rescues by boat were occurring all through Southwest district and up the Anacostia Basin. Reagan Airport remained drowned, and there was no passable bridge over the Potomac all the way upstream to Harpers Ferry. The Great Falls of the Potomac were no more than a huge turbulence in a nearly unbroken, gorge-topping flow. The President had evacuated to Camp David, and now he declared all of Virginia, Maryland, and Delaware a federal disaster area; the District of Columbia, in his words, “worse than that.”

Charlie’s phone chirped and he snatched it to him. “Anna?”

“Charlie! Where are you!”

“I’m still at the office! Are you home?”

“Oh good yes! I’m here with the boys, we never left. We’ve got the Khembalis here with us too, you got my e-mails?”

“Yes, I wrote back.”

“Oh that’s right. They got caught at the zoo. I’ve been trying to get you on the phone this whole time!”

“Me you too, except when I fell asleep. I was so glad to get your e-mails.”

“Yeah that was good. I’m so glad you’re okay. This is crazy! Is your building completely flooded?”

“No no, not at all. So how are the boys?”

“Oh they’re fine. They’re loving it. It’s all I can do to keep them inside.”

“Keep them inside.”

“Yes yes. So your building isn’t flooded? Isn’t the Mall flooded?”

“Yes it is, no doubt about that, but not the building here, not too badly anyway. They’re keeping the doors shut, and trying to seal them at the bottoms. It’s not working great, but it isn’t dangerous. It’s just a matter of staying upstairs.”

“Your generators are working?”

“Yes.”

“I hear a lot of them are flooded.”

“Yeah I can see how that would happen. No one was expecting this.”

“No. Generators in basements, it’s stupid I suppose.”