"Except," I said, "now the river is shut off." I waved toward the nearest streetlamp, still bright and undimmed. "There'll be power until the plant uses up the water in the intake pipes. Beyond that… if the Sparks are smart, their electric cage has emergency batteries to deal with a short power outage; but if the cage normally soaks up most of the energy from Niagara, it's going to burn out its batteries fast. Then the Lucifers will escape, and there'll be hell to pay."

"And we know who created that blasted dam," Impervia muttered.

"Sebastian and Jode," Pelinor said.

I thought he was answering Impervia; but when I glanced his way, he was looking down the road that led back to the center of town.

Two figures were walking toward us: a teenage boy and girl.

They walked hand in hand-bare hands, no gloves or mittens. The air around Sebastian must have been warming itself for his comfort. As for Jode, the Lucifer didn't seem bothered by anything so paltry as a late-winter chill.

Jode looked exactly like Rosalind; and I found it disquieting to watch the girl cuddle up to Sebastian when I'd seen her corpse the previous night. Appalling how lively she appeared-more animated than I'd ever seen the real Rosalind. This version was laughing at something Sebastian said, slapping his arm in mock offense, then nuzzling and kissing his ear.

Nothing like the melancholy girl I'd known.

It amazed me Sebastian couldn't sense something wrong. Every gesture this Rosalind made seemed false: the touching, the giggling, the giddy flirtation. Jode was laying it on thick; yet Sebastian returned every kiss and whisper. No matter how strong he might be with psionics-powerful enough to stop Niagara Falls-Sebastian was nothing more than a sixteen-year-old who could be exploited by his hormones. Jode had wedded him, bedded him, then brought the boy to the power station before the post-nuptial euphoria wore off.

They hadn't noticed us yet. Our group looked no different from other tourist parties, staring blankly into the gorge and wondering where the Falls went. We were also bundled up in coats, hats, and scarves, which would make us difficult to recognize in the dark. Jode was watching for trouble-in between attentive pats and snuggles, the faux Rosalind found excuses to turn her head this way and that, keeping a constant lookout-but even the Lucifer couldn't have guessed how many forces had converged on Niagara: Dreamsinger, the Ring of Knives, and of course, a small but determined band of teachers.

Not that we teachers amounted to much. We'd never even discussed a strategy for dealing with this situation. Violence certainly wouldn't work; if, for example, Impervia attacked Jode, Sebastian would immediately use his powers to protect his "Rosalind."

Our best hope was talking sense to the boy-and not just saying, "She isn't Rosalind." We had to prove Jode was evil.

A good place to start would be pointing out how destructive that big dam was. Whatever story Jode had invented, we could make Sebastian realize that his wall across the river would cause severe flooding. Upstream of the dam, water must be accumulating at a fearsome rate, spilling over the banks, deluging inhabited land. We had to make Sebastian care about the possibility of drowning people, animals, houses, farms; but at the moment, he was too busy kissing his beloved "Rosalind" to picture the consequences of what he'd done.

"I'll talk to Sebastian," I told the others in a low voice. "I know him best." I took a step toward the boy, but Pelinor grabbed my arm.

"Better let me do this," he said. "You're no fighter, Phil, and Jode might try some tricks."

"Then I should go," Impervia said.

Pelinor smiled. "Sorry, old girl, but you're not quite the right person for tactful discussion."

"And you are the right person?"

"I'm a knight," he said. "Fighting the foe and parlaying honorably. What I was born to do."

Without giving anyone else a chance to speak, he moved out into the roadway.

Pelinor planted himself directly in Sebastian's path. "Fine night, isn't it?" he said in a hearty voice. "Bit quiet all of a sudden."

Sebastian and Jode were ten paces away from the knight: twenty paces from the rest of us. The newlyweds stopped and stared; Sebastian just gaped, astonished that someone from the academy had tracked him down… but the Lucifer's eyes filled with hatred. Jode obviously knew who Pelinor was. As I'd suspected, the shapeshifter must have spied on our school, getting to know Sebastian and his teachers.

"We have to talk," Pelinor said. He kept his eyes on the boy, not even glancing at Jode. "Your girlfriend isn't-"

Jode screamed: drowning out the rest of Pelinor's words. The next moment the Lucifer hurtled forward-faster than the real Rosalind ever ran in her life. Metal flickered in the lamplight and I shouted, "Blade!" Jode had whipped out a sword from a sheath at its hip: a rapier, one of the weapons missing from the case in Sebastian's room. The weapon's point came up with inhuman speed, aiming for Pelinor's heart as the alien sprinted to close the gap.

If I'd been in Pelinor's place, I would have been skewered: caught flat-footed, numbly staring at the incoming blade. Even Pelinor didn't have time to draw a weapon of his own-but knight or border-guard, Pelinor was no stranger to sneak attacks. He twisted aside at the last instant, batting away the lethal tip of the rapier with his arm. Cloth ripped as the sword-point slit his coat-sleeve… but now he was inside the arc of the blade and relatively safe from being stabbed. The rapier was purely a piercing weapon, with no cutting edge to harm opponents close in.

Unfortunately, Jode wanted to be close in. Perhaps that had been Jode's plan-the Lucifer might have known Pelinor would evade the thrust and come within reach. Jode's body blocked Sebastian's view of its face; therefore, the boy didn't see the false Rosalind's features dissolve into a curdled white mess… as if the lips, the nose, the eyes, everything, had putrefied into maggots.

Pelinor grimaced with revulsion and retreated a step-still keeping up his arm to prevent a rapier strike, but distancing himself from the ooze of Jode's face. The Lucifer raised its other hand, the one not holding the sword… and I could see its fingers had been replaced by another mass of curds, a soft cream of white chunks. The gooey hand darted toward Pelinor's nose with a boxer's punch; but when Pelinor tried to deflect the blow, the alien's entire forearm spurted out of its coat-sleeve, like slime shot out of a hose.

It hit Pelinor full in the face: splashing across his cheeks and mustache, then flattening outward to cover every bit of exposed skin. Pelinor's hands came up, clawing in a frenzy to get the stuff off… but the fat moist chunks evaded his efforts, dodging from his grasp.

Beneath the damp white coating, Pelinor bellowed in anger and pain. The sound was muffled. Smothered. Choked.

Jode's puffy curd face quivered and refocused, once more shaping itself into the likeness of Rosalind. For a moment the alien leered at us as if to say, "You people are fools." Then it jumped backward, retreating enough that Sebastian finally got a view of Pelinor's scum-covered face. "I told you!" Jode said in Rosalind's voice. "It's not your teacher, it's a monster made by my mother's sorcerers. Just a bag of skin filled with pus. When I hit it, you see what happened. It went all gooshy."

Pelinor tried to object: to tell Sebastian the truth. The only noise that came out of his mouth was a suffocated mumble, broken off quickly… as if the curds had poured down his throat as soon as he opened his lips.

"Sebastian," I said, stepping forward, "you know who we are-"

"Don't listen, don't listen!" Jode-Rosalind screamed. "You can see they aren't real; they're just goo!" The Lucifer waved its sword toward Pelinor. It couldn't gesture with its other hand, because that hand was smeared across Pelinor's face-Jode's coat-sleeve dangled empty from the elbow down.