She whirled back around toward Nick. He had his hand out, and in his open palm, she saw he was holding the three remaining bullets that went with Adrian’s flintlock pistol. Except, they didn’t look right at all, because they weren’t dark gray lead anymore. They were glowing, shining even in the dim light—

They had turned to gold.

“This isn’t possible,” Nick whispered.

But Hailey knew he was wrong. It wasn’t just possible, it was real, it was happening. It was—

It wasn’t. Because suddenly the three bullets darkened against Nick’s palm, and a second later, they’d returned to their original state. Cold, unremarkable lead. The tone from the bell was still echoing around them, but the feeling Hailey had felt just a moment before—the intensity, the internal, almost cellular vibration—was gone.

“They were gold,” Hailey said. “For a second, they were gold. But it didn’t last. It wasn’t permanent—”

A sudden rending sound interrupted her midsentence, and Hailey turned back toward the bell. She saw, in awe, the crack as it appeared, working its way down the front of the bronze, all the way to the bottom. The bell was fracturing right in front of her. And as it did, the tone changed even more, bending toward something dull, unpleasant.

Hailey took another step back. And then she realized, there were other noises beyond the sound of the bell. It took a moment to recognize that they were sirens.

“The police are on their way back,” Nick said. “We have to go.”

The clapper was slowing now, in its arc within the bell, and the tone, unpleasant as it was, grew softer as the sirens grew louder. Hailey was trying to understand what had just happened. Revere’s equation—the sound curve he’d molded into the eagle’s wings—had been made real, translated by the Liberty Bell. The secret, holy grail of alchemy, the philosopher’s stone, that could transform lead to gold—but it had only been a temporary effect. It hadn’t transformed the lead—it had only momentarily rearranged it.

She shook her head. It didn’t make sense.

The box in her backpack that had held the clapper was made of gold. The note that had been inside the box along with the clapper had read: From she who made the box. Hailey had thought the note had referred to the Liberty Bell itself. But she wondered—what if it didn’t?

What if the bell wasn’t the end of Revere’s alchemical inquiry?

“A mathematical proof,” she whispered.

“What?” Nick asked.

He was staring down at the lead bullets in his hand. He looked bewildered. Something incredible had happened, they had gotten so close to something immensely powerful. But then, just like that, it had slipped away.