Teomitl's hands tightened around hers. "I never lie, either," he said. "I'll protect you." He surprised me; I would have expected him to dismiss the old woman, as he'd dismissed the peasants on our last hunt together. But Chalchiutlicue's gift had moulded him into someone else entirely.

"From what is coming?" Her voice was fearful.

"As best as I can. But you have to tell me."

The old woman didn't speak for a while. "You'll remember me," she said. "Ahuizotl. You'll remember me."

"Yes," Teomitl said. And although he spoke in a low voice, the whole hut vibrated with his power, and for a moment the wrongness coiled within the walls abated. "I'll remember you. Where did Mazatl go?"

"It's the day," the old woman said. "The day he leaves his childhood name behind. The day to enter the House of Youth, you see."

I didn't think there would be a House of Youth. What Mazatl needed to learn about war and his place in the world, he'd be told by his father.

"Yes," Teomitl said. "The day he takes his true name."

"Yes, yes," the old woman said.

Neutemoc, although he hadn't said anything, was clearly growing impatient. I was growing worried. Mazatl and his foster parents had obviously been gone for some time. Whatever preparations they needed to make would be near completion.

"Where did they go?" Teomitl asked.

"You'll protect me?"

"I'll protect you," Teomitl repeated. "Look." He blew into her face, gently: his breath became a shimmering cloud that wrapped itself around her, making Tlaloc's magic recede. "That way."

"You're strong," the old woman whispered. "You'll keep your word, won't you?" She shook her head. "They went to the heart of the lake. To the place where they plant the tree of the Star Hill, the place where Spring is reborn."

Neutemoc and I looked at each other. "The Great Vigil," we both whispered.

One month after the start of the rainy season, a tree was brought from the Star Hill, where our first Emperor had built a temple to his father, Mixcoatl, the Cloud Serpent. Scores of warriors hoisted the tree upwards, and planted it into the mud at the centre of Lake Texcoco. A girl was sacrificed and her blood poured on the trunk, and into the water; and thus the Storm Lord would grant us His favours for another year of growing maize.

There would be no tree: by now, it would have rotted down to nothing. But something of that yearly sacrifice would remain, some power that could be tapped into.

"I see," Teomitl said, gravely. He blew again on her, gently. The shimmering cloud of his breath expanded to cover her from head to toe. It sank into her bones, one magic to replace another. And as it did so, the old woman faded slightly, as if she stood at a remove from the Fifth World.

"Such strength," she whispered. "Such unthinking strength. Thank you."

Teomitl clasped her hands, and did not answer.

"Let's go," Neutemoc said.

Outside, it was easier to breathe, although the rain hadn't abated. If anything, it was stronger: a veil, gradually falling across the land; the endless tears of the Heavens, filling the lakes and canals to over-flowing.

"It's transformed you," I said to Teomitl. "Her gift. Once, you wouldn't have looked twice at that woman."

"Ita" Teomitl shook his head, unable to describe what had happened to him. "It a changes you. To the bone."

"So much?" I asked. I couldn't help wondering if Chalchiutlicue had had some other motive in making Teomitl Her agent, if Her gift had had some thorns we hadn't seen.

Teomitl was looking at the lake. "No," he said. "But that woman in the hut... she felt so wrong, yet it wasn't her fault."

"No," I said, finally. When this was all over, we'd have to see that old woman, to make sure she would survive after Teomitl's protection had cut her off from her family.

The ahuizotls were waiting for us near the boat, their heads half out of the water. They appeared more curious than hungry. But The Duality curse me if I trusted those beasts to do anything more than obey Teomitl.

"It's not so far," Neutemoc said.

I snorted. "Not so far. It's at least one hour from here. And I don't think we're doing the right thing."

"What do you propose we do, then?" Neutemoc asked, sarcastically.

"I think we'll arrive too late," I said.

"I don't agree," Neutemoc said.

"Then you can go ahead with Teomitl, and scout. But I'm going back to get reinforcements."

"We don't needa"

"Oh? You can defeat a powerful god's agent, and his creatures, all by yourself? Last time I saw, you were busy being wounded."

"Don't toy with me," Neutemoc said.

"I'm not toying," I snapped. "I'm telling you to be careful for once. Or is that not a warlike virtue?"

"You know nothing of war," Neutemoc said, softly. "Don't presume to judge."

"What other choice is left to me?" I asked, angrily. "You won't judge yourself."

"I don't think it's quite the right time for this," Teomitl said. He was sitting in the boat, lounging in the back as if it were a comfortable chair.

Neutemoc's face was closed. "Maybe not," he said. "But things have to be clear, don't they?"

"Enough," Teomitl said. Again, he didn't raise his voice, but it cut through every word I might have thought of. "Reinforcements are probably going to be useful. Duality priests?"

I shrugged. "Whatever I can find." I hoped it would be Duality priests, though I'd have preferred Ceyaxochitl and Yaotl at my side, even over a dozen of them. But the priests were fierce fighters.

"Very well," Teomitl said. "We'll leave you in Tenochtitlan, and go on to the tree and see what's going on." He raised a hand to forestall my protest. "We'll be careful, never fear. I don't intend to get killed before I get a chance to strike."

Neutemoc said nothing. I wasn't so sure he wouldn't rush, but at least he'd have Teomitl to control him. It was amazing how persuasive the boy could be, when he applied his mind to the conversation. A boy who would one day be Emperor. Better not to think about that a not right now.

TWENTY-ONE.

The Great Vigil When I arrived, the Duality House was all but deserted.

"The priests?" the warrior at the gates asked. "I'm not sure if there are any left inside. You can look, though."

My heart sank. "The Guardian?"

The warrior shook his head. "She hasn't come back from the palace."

The Southern Hummingbird blind me. I had counted on Ceyaxochitl not being there, but not on all the priests leaving.

I found two priests in one of the rooms at the back: an old man and an old woman, who sat with Mihmatini, sipping hot chocolate.

"Greetings," I said. "I was looking for help."

The priests acknowledged my presence with a nod of their head. "I'm not sure you're in the right place," the old priestess said. "We're somewhat depleted at the moment."

"Help? What kind of help?" Mihmatini asked.

"Against creatures of Tlaloc."

The old priest nodded, sagely. "There's been trouble all over Tenochtitlan. The waters rising, and people mauled by things they couldn't see."

The creatures. Neutemoc had been wrong: the child had come into his full powers, and he wasn't shy about using them either. This wasn't good. Not good at all. "That's where all the others are?"

The old priestess nodded. "Emergencies. We're a ah, staying here as a precaution. Keeping the wards up."

The priest took a sip of his cup. "But if it's urgent..."

It was urgent. But Mihmatini was in the Duality House, as well as Neutemoc's whole household. Two old priests wouldn't make that much of a difference against what was coming. "No," I said. "Given how badly things are turning out, it's more urgent to keep a safe place. I'll a find help somewhere else."

Mihmatini had been relatively silent until now. "I'll come with you," she said.

I shook my head. "Stay here."

"Because you think I'm too weak to fight?"

The Duality preserve me, why did everyone take what I said badly? "No," I said. "Because you're not putting yourself in danger."

Mihmatini set her cup aside, but didn't speak.

"Do you really want to fight those creatures again?"

"They frighten the soul out of me," Mihmatini said, finally. "But my wardsa"

"Won't last in this rain," I said. "And it takes you too much time to draw them. Stay here. You'll be safe. No need to endanger your life."

Mihmatini puffed her cheeks, with a familiar thoughtful expression. "Is there need for you?" she asked.

I stared at her for a while; trying to imagine myself ensconced in the safety of the Duality House. But I couldn't. "It's my place," I said. "No matter how hopeless things are."

I couldn't read her expression. "Your place," she said. She shook her head, as if exasperated. "You're impossible, you know. You and Neutemoc, come to think of it."

I felt embarrassed; though I didn't know why.

Mihmatini shook her head. "I'll stay here," she said. "The children are frightened, in any case. And you a you're not leaving until I set new wards on you."

I made a mock-frightened face. "As you wish."

Mihmatini snorted. "What did I say? Impossible, both of you."

On my way out of the Duality House, I stopped in the barracks, looking for Ixtli. I found him supervising a mock-battle in one of the larger rooms. Three of his Duality warriors were taking on another three, hacking at each other with their macuahitl swords, the harsh sound of wood striking stone echoing under the carved rafters of the ceiling.