Grim had the stone on his palm; he was squinting at it the way a scholar might look at a manuscript in an unknown language. Before I could take a closer look, our two minders came up beside us. Onchú had turned pale; I realized, belatedly, that his memory of what had happened to him here must still haunt him, and that setting foot on the island must have required a great deal of courage. Didn’t Grim and I dream of Mathuin’s lockup every single night?

I motioned to Grim to put the stone in his pouch. As we made our way down to the river, I listened to the rhythm of the creature’s voice, and when it paused for breath, I whispered, “I mean you no harm. I’m here to help.”

It was only when we had waded back across the river, and walked up through the forest to Geiléis’s house, and retreated to our quarters so Grim could change his wet clothing, that he took the stone from his pouch, and we saw that the markings traced on the gray were not the random patterns found on some of the river pebbles, but drawings scratched there with a sharp implement. I sucked in my breath, turning the thing over. Nausea welled in me. In my hand was the rusty nail; in front of me was the filthy wall of my cell, and the rows of lines I’d made there, one for each day, each endless, vile day of my incarceration. A sound burst from me, half sob, half oath.

Then, Grim’s hand gentle on my shoulder. “It’s all right,” he said. “It’ll be all right. Deep breath, now.”

For once, I did as I was told. “Flea-ridden cesspit,” I muttered. “Will it never go away?”

“Can’t answer that.” Grim was pouring water into a cup. “Drink this. I’ll get a brew on.” He busied himself while I sat down on the bench and wrestled with my troublesome thoughts. Mathuin. The truth was, that man and what he stood for would not go away until I found the courage to do something about him. And I had the opportunity now. I could head south with Flannan on Midsummer Day. I could make sure the chieftain of Laois got his just deserts at last. I could have vengeance. Then, surely, the evils of the past would start to fade.

Grim went out with a bucket in hand, heading for the pump. He’d left the stone on the table beside me. I could not bring myself to pick it up again, but I looked at it; studied the markings, swallowing bile, forcing my unruly mind to settle to the task in hand. And I realized that this had been no missile intended to kill me, or to force me off the island. It was the answer to my whispered question. The drawings were crude, as if executed by a clumsy child. A circle with lines coming out from it: the sun. A stick figure with something in its hand—was that an ax? Another figure, crouched with its head against a bench or box.