BERTRAND WAS HERE, 1898.

Tell Richard I will love him forever.

I AM ALREADY A GHOST.

Let me out,

let me out,

let me out.

Jaime stopped to look out of one of the windows. He had a perfect view of the sapphire-blue East River and Manhattan sparkling like a mirage on the other side of it. He couldn’t imagine being quarantined here and seeing that city, knowing it was so close and understanding that you might never see it again. He shivered.

“I wish we knew what we were looking for,” said Tess. “We don’t have that much more time.”

Theo said, “That’s why I suggested we split—”

Jaime glared. Theo shut up.

They moved on. Pawing through books and papers, sifting through piles of wood and rubbish, reading the notes and graffiti. Just as he was beginning to despair that they would ever find what they were looking for, they came across more graffiti chalked or etched into the walls. One line curled around the blue-tiled room from one wall to the next, scrawled in chipped red paint:

BURY ME RIGHT NEXT TO LOUIS MG,

THE MOST TALENTED MAN IN THE WHOLE OF THE CITY.

“Who’s Louis MG?” said Tess.

“I don’t know,” Theo said.

“Me, neither,” said Jaime. He pulled out his sketchbook and wrote the message into it.

“Do you think it’s any more important than the others?” said Tess.

“It’s the only thing written in red. And it’s the only writing we’ve seen that indicates a last name. And something about the word bury.”

“Buried treasure?” Theo said.

“Maybe,” said Jaime.

Just then, a loud crash made them all jump. Tess grabbed Theo’s arm; Jaime grabbed Tess’s.

“What was that?” Tess whispered.

“The house settling?” Theo suggested. “At least, that’s what Dad always says.”

They stood as still as they could, listening. Jaime couldn’t be sure if it was his imagination, but he thought he heard footsteps somewhere down below. His skin prickled.

“Do you guys hear that?” he said. Say no, say no, say no.

“Yes,” said Tess. “Someone else is here.”

“Aunt Esther,” Theo said, but he did not sound confident.

Jaime said, “There has to be another staircase on the other side of the building.” He pointed, and the three of them crept as carefully and quietly as they could down the hallway toward a staircase they could only hope existed, and was still usable. But Jaime was right. At the end of the hallway, there was another staircase. They stood listening on the landing.

“Nothing,” said Theo.

“I don’t hear anything, either,” Tess said.

“Maybe it was something else?” Jaime said, relieved. “An animal or—”