“What?” I said. “What do you mean?”

“Poison,” said Finbar. He was leading me quickly through the archway to the gardens. Both of us had the ability to move fast and silently over any sort of terrain. It came of growing up half wild. We had, in fact, a variety of unusual skills.

Once we were in the stillroom, and both outer and inner doors bolted, I made Finbar sit down and explain. He didn’t want to; his face had that stubborn expression it sometimes took on when the truth was painful or hurtful, but had to be told. One thing neither of us ever learned was the skill of lying.

“You’ll have to explain,” I said. “You can’t just say poison and then stop. Anyway, I can tell what you’re thinking. I’m twelve and a half now, Finbar; I’m old enough to be trusted.”

“I do trust you, Sorcha. It’s not that. It’s just that if you help me now, you’ll be at risk, and besides, it’s…” He was twisting the end of his hair with his fingers again. He shut his words off, but I was tuned to his thoughts, and for a moment he forgot to shield them. In the darkness of the quiet room I caught a terrifying glimpse of a glowing brazier, and mangled, burning flesh, and I heard a man screaming. I wrenched myself back, shaking. Our eyes met in the horror of our shared vision.

“What sort of poison?” I asked unsteadily, my hands fumbling for tinder to light a candle.

“Not to kill. A draft strong enough to send a man to sleep for the morning. Enough of it to doctor four men; and tasting fair, so they will take it in a tankard of ale and not know different. And I need it before sunrise, Sorcha. They take their breakfast early, and the guard changes before midmorning. It’s little enough time. You know how to make such a potion?”

In the dark, I nodded reluctantly. We two need not see each other, save in the mind’s eye, to reach an understanding.

“You’re going to have to tell me,” I said slowly. “Tell me what this is for. It’s him, isn’t it? That prisoner?”

The candle flared and I shielded it with my hand. It was very late now, well past midnight, but outside there were subdued sounds of activity, horses being moved, weapons sharpened, stores loaded; they were preparing already for a dawn departure.

“You saw him,” said Finbar with quiet intensity. “He’s only a boy.”

“He was older than you,” I couldn’t resist pointing out. “Sixteen at least, I thought.”

“Old enough to die for a cause,” said my brother, and I could feel how tight stretched he was, how his determination to make things right drove him. If Finbar could have changed the world by sheer effort of will, he would have done it.

“What do you want me to do? Put this Briton to sleep?” By the dim light of the candle I was scanning my shelves; the packet I wanted was well concealed.