“Rookskill holds answers. That is what I read in the ledger right before time was up. I need to find at least some of the remaining answers here. Maybe by finding another artifact like the snake or this cuff. Or maybe in a book.” He paused. “You seem to know the library, so I’m wondering if there’s a book—”

“No, I don’t know the whole library, not really,” she interrupted. “I know about magical creatures. If you want to know what’s in the library—in fact, if you want to know anything about Rookskill, you need Leo.”

“Leo?”

She nodded. “I know he seems a little strange. But Leo’s spent hours in that library. Hours learning about Rookskill.”

“Right, then. Let’s go find Leo.”

Isaac glanced out the window once more, and then paused and leaned against the glass. Was that . . . ? It looked like . . . No, it couldn’t be. Isaac blinked. And when he looked again, it was gone.

“What?” Amelie asked.

“Nothing,” Isaac said. “For a second, I thought I saw, well. Just my imagination, for certain.” He laughed. “At the top of one of those trees, I thought I saw a dragon.”

*   *   *

Amelie and Isaac found Leo in the library, reading.

“Brilliant,” Amelie said. “Where’s everyone else?”

Leo shook his head. “Dunno.”

“Leo, I need help,” Isaac said.

Leo gave an embarrassed half smile. “I’m not much of an adventurer.”

Isaac said, “I need help finding something that may be in the library or somewhere else in the castle.”

“Oh!” Leo brightened. “In that case . . .”

“What do you know about a Vault that holds magical artifacts?”

“Vault?” Leo echoed. He stared up at the ceiling. “Artifacts. Right.” He stood and walked to the other side of the library, mumbling to himself. He pulled the ladder along the wall until it came to rest in the far corner, and climbed it to the topmost shelves. “Here we are. Come. I’ll hand these down.”

Amelie stood on a lower rung of the ladder, passing books from Leo to Isaac. Isaac took the first one and turned it in his hands.

The title glittered gold. Secrets of the Vault: The Revised Oxford Translation.

While Leo was handing down books, Isaac told him about the time travel he took with Amelie.

At one point, Leo paused and said, “So there was another door that appeared and disappeared, like the one you saw in Alexandria? And you think the astrolabe was left in this Vault place by Hypatia way in the past? Interesting.”

Soon there was a stack of books on the table, and Amelie and Leo joined Isaac to read the first one he opened.

The title page read, The Artifact Hunters’ Diaries, Years 1753–1785. As Noted by Guardian Q. And below that, the symbol of the eternity knot.

Isaac looked up and met the others’ eyes. “This is it,” he said. “Very nice, Leo.”