"Shooting?" Bing said. "With guns? But that would scare the horses."

"Then you'd better go," Impervia said immediately. "Thanks for your help, but it's time you went home."

"You don't need a ride back to Crystal Bay?" He looked at Impervia with hurt in his eyes-as if he didn't want to be sent away just yet. "I mean… you'll have to head for the bay eventually. Your ship's still there."

Impervia dropped her gaze for an instant, then forced herself to look Bing in the eye. "Getting back to our ship is the least of our worries. Now you'd better leave before things turn dangerous. Otherwise…" She paused. "Otherwise, the horses might get hurt."

She'd found the right argument to get Bing to leave. He gave her a regretful look, then swung himself up to the driver's seat.

"I'll be spending the night at the Peacock," he said. "Tisn't good to drive country roads in the dark this time of year. If you're in need of transport, I'll still be around come morning."

"Let's hope we will be too," Impervia told him. "On your way now."

She reached up, and for a moment I thought she would pat Bing on the thigh… but she shifted her hand at the last moment and touched the seat instead: resting her fingertips lightly on the padded bench, letting them linger for a moment before drawing back. "Go," she said. "Thanks again."

"No trouble," Bing answered. "You have a good night."

"You too."

Bing gave the reins a flick and the horses started forward. Impervia stared after the coach until it disappeared around a bend in the road.

"At least it's quiet," the Caryatid said. "No sign that there's been a battle. I think we've got here before Sebastian."

The Caryatid's voice sounded unnaturally loud-as if she were shouting, though she was only speaking normally. Impervia must have sensed the same odd loudness because she answered in almost a whisper. "It's a pity we don't have Myoko. She could have given the door a telekinetic nudge, just to see what happens."

"We don't want to see what happens," I said. My voice sounded loud too. "We don't want anyone to know we're out here," I whispered. "We just intercept Sebastian and leave before Dreamsinger notices us."

"Still," said Pelinor, "it would be interesting to scout their defenses, don't you think? We could throw a stone…"

"No!" shouted the rest of us in unison.

The word echoed off the power station's cement walls and drifted into the night. It took a long time to fade. The world had gone silent-uncannily so. Some important sound was missing…

"Merciful God," I breathed. Whirling around, I ran to the edge of the road and looked down into the gorge.

Bare rock glistened in the spill from the streetlamps. Water languished in dozens of pools, and a small stream ran through a channel down the middle of the river bed… but the roar was gone. The spray had settled. The colored spotlights danced for the tourists across a cliff-face that had never been exposed to open air.

I realized why our voices all seemed so loud-why the world had gone so quiet.

Someone had turned off the Falls.

The others joined me at the railing, everyone looking at where the Falls should have been.

"Damn," whispered the Caryatid. "There's something you don't see every day."

Across the gorge, on the Rustland side of the Falls, people were already clambering over the safety barriers and down onto the rocks where the river was supposed to be. Idiotic bravado-I suppose they wanted to be able to tell their friends they'd walked across Niagara Falls. As soon as those people ventured onto the river bed, the natural perversity of the universe should have sent the water sweeping back in a solid wall of crashing froth. But no such torrent appeared… even when a teenage boy reached the weak brook trickling down the middle and sloshed about in the current, laughing to his friends.

Pelinor said, "Oh, look. Where did the water go?"

He turned to me for an answer. Pelinor always believed that because I was a scientist, I could explain anything. "Umm," I said. "Uhh. Hmm. The only thing I can think of is that the entire river is being diverted into the power station. There are sluices upstream to take in water and pipe it through the generators. I didn't think they had the capacity to siphon up the whole river, but if Dreamsinger really wants to maximize electrical production-"

"Phil," Annah interrupted, "there's another explanation."

She was peering upstream, shading her eyes from the nearby streetlamps. The river in that direction was mostly dark: a bridge extended from the Rustland side to an island in the middle of the rapids (or where the rapids should have been), but beyond the shine of the bridge-lights, the river disappeared into blackness. Deep blackness. "I can't see anything," I said.

"Neither can I," Annah replied. "It's not normal shadow. It looks like a wall."

"A wall?" I squinted again. Utter blackness covered the river beyond the bridge; but when I looked to the sides of the waterway, I could see vague outlines of buildings, streets, trees: normal things in normal darkness, not utterly swallowed by oblivion.

I shifted my gaze back to the river and moved my eyes slowly upward. Black, black, black… then suddenly stars. As I watched, a drifting tatter of cloud disappeared out of sight behind the blackness-occluded by that dark impenetrability.

Someone had lowered a curtain of blackness onto the Niagara River. A wall indeed. Or more precisely, a dam.

By now the others had seen it too. "What is it?" Pelinor whispered.

A trillion trillion nanites, I thought. A vast barrier of them, clustered together to clamp off incoming flow. "It's a dam," I said. "Blocking the river. I'll bet you anything it's positioned to cut off the power plant's intake sluices." When Pelinor looked at me blankly, I told him, "The generators need water to make electricity. That dam blocks the water… thereby shutting down the generators."

Beside Pelinor, the Caryatid's face had turned grave. "So the Sparks can't produce electricity. Whatever they use it for will stop working." Her hands gripped the guard rail tightly, as if she wanted to crush the metal in her fingers. "For some reason, I keep picturing a thousand shapeshifters like Jode held captive in an electric cage. The Sparks lock Lucifers there whenever they catch one… and the Keepers of Holy Lightning maintain the generator turbines to make sure the power never goes out. Is that possible, Phil?"

"An electric cage?" I thought about it… and I recalled the violet glow surrounding Dreamsinger's armor: a vicious energy barrier that could melt bullets. The armor's force field kept things out, but the same technology could surely lock captives in. "It's very possible," I said. "Is this just some scary notion that popped into your head? Or is it another sort of a prophecy kind of thing?"

"I don't know." The Caryatid's voice was weak and distant. "It's not my usual kind of premonition… but the image won't go away."

Pelinor took her hand and patted it. The rest of us averted our eyes to give them some privacy. Impervia muttered to Annah and me, "Much as I respect the Caryatid's premonitions, I have my doubts about this one. Spark Royal doesn't jail its enemies; it executes them. Keeping Lucifers alive is foolish, no matter how carefully you lock them up."

"But maybe," I said, "Spark Royal needs Lucifers for something. Or maybe the Sparks' alien masters don't want the Lucifers killed. If so, you couldn't keep a shapeshifter in a normal prison-you'd have to build some kind of energy confinement field."

"And everything else," murmured Annah, "the lights and music in this city-it's just a cover. The Sparks realized they couldn't keep the power station a secret: local people would know the place was in use. If nothing else, the intake sluices and outflow pipes must need maintenance from time to time; and you can't hide a bunch of workers playing around with giant underground plumbing. The Sparks pump a small ration of power to the public so people think they know what the generators are doing. But the real purpose of this station is to imprison Lucifers."