While Teomitl was giving instructions to the two warriors, I sidled closer to Nezahual-tzin. "You said you weren't responsible for his recovery."

"I am not."

"Thena"

Nezahual-tzin nodded. His eyes were still on Teomitl. "I don't believe in miracles. If he's cured, someone must have helped."

"Chalchuihtlicue?" I asked.

"Your sister said that she'd tried summoning Her earlier, and that it had been in vain."

"But whoa?"

"I don't know," Nezahual-tzin said, grudgingly. He had never liked admitting ignorance. "But I will find out." He looked at Teomitl a who seemed in the middle of an animated conversation with the warriors, with the occasional interjection from Mihmatini. "Can I speak to you outside?"

I felt, suddenly, like a conspirator. "Surely anything you have to say to mea"

"I'm afraid not. It's outside, or not at all."

I sighed, casting another glance at Teomitl. I guessed it had to do with my student a whom Nezahual-tzin had little liking for.

We walked out of the room, and back into the courtyard. The air was thick with the smell and smoke of copal incense; the altar atop the pyramid shrine covered in a mound of maize cakes. Priests with black-streaked faces were sweeping the courtyard with rush brooms, keeping it clean so the Duality would always been welcome.

"What do you want?" I asked.

Nezahual-tzin smiled. "Don't be so hostile. You know I'm working in your best interest."

"Until you decide you no longer need us." He had done it often enough, after all a last year, when I'd had a death sentence hanging over my head, he'd all but sold me back to Tizoc-tzin.

He shrugged. His eyes rolled up in their sockets, revealing the milky white of faraway stars. "You heard Teomitl. Someone is acting against the Empire."

"And?"

"You think a mere courtesan would want this?"

"Why not?" I asked. "You forget. Her goddess has enough of a grudge against the Mexica Empire."

Nezahual-tzin shook his head. "There's something wrong with this."

There was, perhaps a I still needed to examine the black creature, and see if I could identify the traces of magic left on it. And I hated to have to arrest an innocent woman. But Teomitl had a point: the risk was great, and the time for hesitation had passed. "We're the ones investigating this, and as of this moment we don't have any other leads. If you want to investigate, please do."

I'd intended to make clear to him that barging in with his criticism wasn't appreciated, but he took me seriously. Or, knowing him, perhaps he understood and didn't care. "There was a merchant involved, I understood."

I didn't bother to ask how he knew. It was either the blessing of Quetzalcoatl the Feathered Serpent, or his preternaturally excellent network of spies. "Yayauhqui."

"Yes, Yayauhqui. You didn't ask the right questions."

"What right questions?"

"I'm told your Fire Priest was wondering what deity Yayauhqui worshipped as a youth."

"I thought there might be something there." Even if there hadn't been.

"Perhaps," Nezahual-tzin said. "But that's not what matters. What matters is Yayauhqui himself."

"I don't seea"

"He was a member of the Imperial Family. A small and insignificant one: I doubt Moquihuix-tzin ever paid much attention to him. He was never a man to pay much attention to the small fish anyway."

"A member ofa"

"You see why it's important," Nezahual-tzin said soberly.

"It could still be something else."

He shook his head. "You don't understand, Acatl-tzin. Tlatelolco will not forget. They'll never forget."

I looked at him curiously. Why such animosity? He had been barely a child at the time of the war that had cost our sister city their independence. "What makes you say that?"

"You have been to Tlatelolco."

"Only the marketplace," I said.

"You'll have missed the most important thing," Nezahual-tzin said. "Their Great Temple."

"What of it?"

"It's a ruin," Nezahual-tzin said. He sounded sad, or angry a I couldn't tell. "The limestone has cracked and dimmed; the frescoes have all but vanished. Not a human hand has touched it for eight years; not a single sacrifice has been offered there. To the gods, it might as well be dead."

"Why?" I asked, and thought of the answer before Nezahual-tzin could speak. "Tlatelolco worships within Tenochitlan's Sacred Precinct. Tlatelolcans shouldn't be allowed to repair something that has no use." The Great Temple: the focal point of worship, the pride of one's city a the beating heart, the entrails.

"And they pay tribute every eighty days; send men to keep the temple of Huitznahuac in good repair, and feathered costumes every year. That, on top of the exactions the Tenochca warriors committed within the city on the day of the battle."

"You weren't there," I said.

"My father was," Nezahual-tzin said. His eyes were brown again, but with a particular, distant glaze, as if he could actually see into the past. Knowing him, it might well be the case. "But for him, Moquihuix-tzin might well have succeeded in his bid to overthrow the Tenochca domination."

"I still don't seea"

"You don't know how the war started."

"Over his wife," I said, slowly. Teomitl's sister, the one Revered Speaker Moquihuix-tzin had neglected.

"No," Nezahual-tzin said. "It started because, when Moquihuixtzin's wife found refuge in Tenochtitlan after one too many nights of neglect, she brought word of a plot a an alliance between Tlatelolco and Culhuacan a both cities would regroup their armies, storm Tenochtitlan and send every man and woman of Tenochca blood soaring into the Heavens."

"That'sa"

"Not something the Triple Alliance boasts of." Nezahual-tzin shrugged. "You can see how ill-informed it makes us seem. That it should take a woman to bring us word of what was right under our eyes."

I couldn't help it. "You don't like women, do you?"

"On the contrary," Nezahual-tzin said. "I think most people underestimate them, often unfortunately. Your sister, for instance, is worth perhaps more than all three High Priests combined, but there'll be few members of the clergy crowding to offer her any kind of official position. But never mind, that's not the point."

"I wish you would get to it," I said between clenched teeth.

Again, that graceful shrug, that mocking smile, and a hovering behind him in the afternoon light a the shadowy form of an emerald-green serpent, with a mane of black and red feathers, and eyes that glowed like pale stars. "Merely that Tlatelolcans plot. They've always been good at it, and they can hide their resentment for years if need be a waiting for the best moment to strike."

"You're generalising from one example," I said.

"Perhaps," Nezahual-tzin said. "But the evidence against your merchant Yayauhqui is exactly as slender as that against Xiloxoch."

"Then what do you want? That we should arrest him as well?" And spark off another war between Tlatelolco and Tenochtitlan?

"I want you to consider this, and to remember my warning. There are men you shouldn't cross, Acatl. Beware of Tlatelolcans, especially if they seem helpful."

He'd unnerved me more than he knew; or perhaps exactly as much as he'd intended to. "I'll keep it in mind."

"Good. Oh, and another thing," Nezahual-tzin said. "You'll want to keep an eye on your student a for his sake and yours."

"Why?" I said, feeling lectured enough for a lifetime. "You've in terfered quite enough in my affairs."

"Ah, but you didn't see."

"See what?"

"The warriors." Nezahual-tzin's voice was slow and gentle, like a mother pointing out a child's failures.

"What about them?"

He shook his head, almost sadly. "One of them started to remove his sandals. He only stopped because his companion gave him a warning glance."