“What was that?” Isla asked, grabbing onto her hair.

More glass shattered. Then heavy footsteps.

“We aren’t alone anymore,” Marly whispered. “Quick! Let’s close this back up.” She pulled the door closed, and Isla and Sai helped her move the painting back in front of it.

“Where are you kids? I know you’re in here!” Someone with a gruff voice tromped around downstairs.

Sai flattened himself against the wall. “I-is that . . . Jay?” he asked, his voice shaking.

“I think so.” Marly gulped. And it sounds like he is in the house!

“What are we going to do?” Isla whispered.

Marly racked her brain. “The hidden stairway!” she said. “We can hide in there.”

“I want to know what you’re doing in my house!” Jay shouted.

“It’s not your house!” Sai shouted back as Marly and Isla gaped at him.

“What are you doing?” Marly hissed.

Sai gave Marly a sheepish look. “It’s not,” he mouthed.

Not the point, Marly thought. “Open the door!” She elbowed Sai. He was the one who had the key.

“It is my house,” Jay said. “And you three are trespassing!”

“Hurry!” Isla pulled on Sai’s arm.

But Sai didn’t unlock the door. “You’re the one who’s trespassing,” he yelled at Jay. He stormed down the hallway. And down the stairs. “We were invited. Were you?”

Marly and Isla raised their hands in helpless frustration. They didn’t have a key to the hidden stairway. What else could they do but reluctantly follow Sai?

Downstairs, the large window behind the sofa had been shattered. Broken glass littered the sofa, table, and floor. And Jay Summerling, dressed in a suit and tie, stood beside the overturned Scrabble game with his hands on his hips.

Sai bent to pick up a baseball-size rock. So that’s how he got in here.

“Doesn’t look like you were invited,” Marly said. Isla hovered behind her.

“Yeah, this is Mr. Summerling’s house, not yours,” Sai said. “He left you out of his will, remember? He left all his treasure to us!”

“So, there is treasure,” Jay said greedily. “What is it? Where is it?” He eyeballed each of them in turn.

Marly pressed her lips together. They all remained silent.

“TELL ME!” he screamed, his angry voice shooting right through Marly. Isla reached for Marly’s hand.

Jay stood tall, took a deep breath, and lowered his voice. “If you don’t tell me where it is, I’ll call the police.” He reached into his pocket and pulled out a cell phone. “I’ll tell them you all broke into my dad’s house and I caught you trying to steal from him.”

“You’re the one who broke in!” Isla argued.

Jay’s smile was pure evil. “I don’t think the police will see it that way. I’m an upstanding businessman. You are children. Who do you think they’ll believe?”

“Us!” Marly said, summoning courage she didn’t know she had. “Because Ms. Lovelace will tell the police she gave us this letter.” She patted the tote bag that hung from her shoulder. “We’re on another treasure hunt, and we can show the police how we got in here. We didn’t have to break a window to get in like you did.”

“Unfortunately, Stella Lovelace is gone,” Jay said.

“What do you mean gone?” Sai asked. He shifted the rock from one hand to the other.

“She’s not gone,” Isla said. “We were just in her office a couple hours ago.”

“Oh, I know.” Jay moved toward them. “I saw you from my own office down the street. I wanted to know what you were up to, so when you left her office, I watched you. Then I followed you. I waited while you went inside the house next door, and then I watched you go in here. I rang the bell. When you didn’t answer, I went back to Ms. Lovelace’s office to find out what was going on. But her office was all locked up. There was a note on the window that says, ‘Out for the rest of the summer.’”

“What?” Isla said, confused.

“Out where?” Marly asked. Why would Ms. Lovelace have suddenly closed up her office in two hours? It didn’t make any sense.

“I don’t know,” Jay said. “And her phone goes right to voice mail. Speaking of phones . . .” He raised his phone. “Are you going to show me the treasure or am I going to call the police?”

Marly, Isla and Sai exchanged nervous looks. They hadn’t actually found the treasure yet. It was probably in that hidden room behind the painting upstairs, but they weren’t absolutely certain of it. Either way, they sure didn’t want Jay Summerling tagging along while they found out. And they were pretty sure Mr. Summerling wouldn’t have wanted that, either.

“Fine. We’ll show you where the treasure is,” Isla said finally.

Marly gaped at Isla. Is she out of her mind?

“Oh, no, we won’t!” Sai argued, blocking the entrance to the hallway and stairs.

Isla got right up in Sai’s face and said, “We don’t want him to call the police.” Then, ever so slightly, she tilted her head toward the fireplace. “I bet you didn’t know there’s a hidden room behind the fireplace,” she said to Jay.

Ah. Now Marly knew what Isla was up to. Isla was so smart!

Curiously, Jay walked over to the fireplace. He scanned the mantel and touched all the bricks. Just like Marly and Isla had done. “How do you get in there?” he asked. He stood with one foot on the marble half circle in front of the fireplace and one foot off.

Isla pointed. “You have to have both feet on the marble.”

Jay narrowed his eyes. “What are you trying to pull?” He still had one foot on the marble and one foot off.

“No, Isla! Don’t tell him. We don’t want him to know where the treasure is,” Marly said. She hoped she sounded convincing. She hoped Jay would think there was treasure hidden behind the fireplace.

“That’s right,” Sai said, walking over to Jay. “It’s our treasure. Not his!”

Jay shoved him out of the way, then stepped back onto the marble. This time with both feet. “How do you get in there?” he asked Isla.

“Like this!” Isla lunged for the underside of a shelf by the fireplace and jabbed something with the palm of her hand. The whole fireplace wall immediately swung around, taking Jay with it.

“So cool!” Sai breathed.

The fireplace wall that faced them now looked exactly like the other one. You’d never know anything had changed. Or that there was a hidden room behind that fireplace.

“Good thinking, Isla!” Marly patted her friend on the back.

Isla beamed.

“I’m glad we locked the metal door in there that leads to the hidden stairway,” Sai said.

Marly nodded. She was glad they’d done that now, too.

“I meant it when I said we don’t want him to call the police,” Isla said. “But we should call them. Should we go over to your house and do that?” She looked at Marly.

“Not yet,” Sai said. “Jay isn’t going anywhere. So let’s go back upstairs and see what’s in that room behind the painting first.”