The pendant was the key to the Vault of magical artifacts. The key was carried by the Guardian.

Hypatia and the Incan man had worn the pendant and made the door appear, so they must have been Guardians in their times.

Mistress Vivienne, who had worn the pendant, was Guardian in her time and said, “I will not return. It’s time for another, who is waiting for me even now.”

Isaac’s father, who wore the pendant, was Guardian in his time.

In the Incan city, Isaac had thought, Please, door, appear and open, and it had appeared and opened.

Isaac’s father gave the key to Isaac because . . . The simplest solution to this question, to Isaac’s question about why he was here at Rookskill, what was happening to him through all these time travels, and what he was supposed to learn along the way . . .

The simplest answer was that Isaac was the newest Guardian of the Vault of magical artifacts.

Isaac took a deep breath as he thought about this huge responsibility.

He shoved the pendant back down underneath his shirt and rose to his feet. He was following this time-travel puzzle so that he could learn how to become the Guardian. How to use magic. How to be the Isaac Wolf he’d always wanted to be—the hero of his own story.

But the best thing—the very best thing—was that he’d made friends along the way. In the diaries Leo had found in the library he’d read about the team—the team of Artifact Hunters that worked with the Guardian. How the team was crucial to success.

Guarding the Vault didn’t have to be something he did alone. Defeating dark magic wasn’t something he had to manage by himself. All the others had magical skills, too. He just had to amplify them, the skills of his friends. His new family.

The Artifact Hunters.

Right, then.

Isaac squared his shoulders and looked at Sir Bedwyr. “We’re going to need a plan. But first things first. Can you, and the rest of them”—and Isaac gestured down the length of the armory—“can you all fight if I ask?”

The ghost knight lifted his head, and a blue light flashed through the visor. The flash was echoed up and down the line of knights, and Isaac heard a soft hiss that sounded like yes.

“All right, then,” Isaac said. The knights could fight with weapons. Isaac would fight with magic.

He heard the familiar pop and Willow hung in the air before him. “There’s been a bit of trouble,” Willow said.

“Colin again?” Isaac asked.

“He’s still missing. But no, this is new trouble. A very bad kind. We like Amelie the best, so it’s really too bad.”

Isaac sucked in a breath. “What do you mean?”

“It’s not very nice,” Willow said, and leaned close. “You’ll have to see for yourself.”