“One row of numbers tells you how to reorder the lines of text, and the other number tells you how many random letters were added to each line. So simple, and yet nearly impossible to crack without this key.”

While still holding the bottle with one hand, Nick had his phone out of his pocket and took a quick picture of the urn. After making sure he could read the numbers off the picture, he finally lowered the bottle—and, abruptly, the effect ended. The urn was again just an urn.

“I need to go somewhere,” Hailey said, her excitement rising, “so I can get to work on the book.”

“What book?” Adrian stammered. “You’re saying those numbers—a Jeffersonian key—”

But Hailey had already returned the mirror to her backpack and was heading through the doorway. Nick was right behind her, and after barely a beat, the professor raced after both of them, trying to catch up. Hailey could barely feel her feet as she moved; she had no idea what they would find in that book, but she knew it was a secret that had been kept for almost two hundred years. And now she had cracked it—with a little help from Nick—and Isaac Newton.

Hailey was close to a jog as she reached the open doorway leading back out into the park—but suddenly, Nick grabbed her arm and yanked her back so hard she nearly lost her balance.

“Shit,” he hissed.

He pulled her to the side, pushing her back against the granite wall at the base of the curved stairs leading upward. Adrian nearly slammed into them—then stepped back, more bewildered.

“What is it?”

Nick ignored him, speaking to Hailey.

“Feds, I think. Or undercover cops. Two cars, on the far curb. At least three badges already on foot, heading this way.”

Hailey’s chest constricted.

“You’re sure?”

“The way they’re dressed. The way they’re moving. The make of the cars. Definitely law enforcement. Which is better than whoever took out the warehouse and Jimmy the Lip, but not by much.”

Adrian’s eyes widened.

“You’re criminals?”

Hailey’s fingers clenched against the cool granite behind her back. If they were caught by the police or the FBI, they would lose the eagle, the book, and any chance at understanding what they had stumbled into.

She looked past Nick and the professor, at the spiral of steps leading up to the top of the obelisk. She didn’t like heights, but there wasn’t much choice.

“Two hundred and ninety-four,” she said.

Nick followed her eyes and realized what she meant.

“We’ll be trapped up there. One way up, one way down.”

“We’ll start with the way up,” she said. She took the lead, and the two of them lunged past Adrian, leaving the professor, stunned and alone, by the bottom of the steps.

Chapter Twenty

Chapter Twenty