Henry raced for the door, but the man from the park caught him in arms that felt as solid as the marble statues from the Louvre. He dragged Henry into the center of the room while Hem closed the heavy door.

“Look … I don’t want you to panic,” Hem said.

“Are you kidding?” Henry spit the words in Hem’s direction, then aimed a backward kick at the man’s knees. He felt a breathy grunt in his ear, and for a second, the man’s stone grip loosened. Henry tried to wrench free, but he couldn’t get away.

Finally, hot-faced and out of breath, he twisted his head around to catch a glimpse of the man’s face. The obsidian eyes that drilled into him, the mustache, the greasy black hair … were all Vincent Goosen. But Goosen’s skin was weathered and pockmarked. This man’s face was younger; his neck was fleshy and pink, with no trace of Goosen’s signature serpent tattoo.

Henry felt hot breath on his neck. “Are you ready to listen?”

“Fine.” Henry stopped struggling and, as soon as the man let him go, turned to face him. “Who are you?”

The man sighed. In the dim light, he looked more tired than fierce. “I am Vincent Goosen —”

“You are not.” Henry glared at him.

“Junior.” The man folded his arms and stared back.

“Oh!” Anna squeaked from the bench by the Monet, where she was huddled with José. Her eyes got huge. “You’re the other son!”

One side of the man’s mouth turned up. His eyes narrowed, and he let out a half laugh through his nose. “To my father, I am no son at all.”

“How’d you get out of prison?” Henry asked.

Anna answered for the guy. “No, he’s not that one. Goosen has two sons, remember? The one who got caught with him and then that other one who disappeared, like, years ago. Only … he’s back now.” She looked at the man. “Right?”

“Like magic,” the man said sadly, holding out his arms as if to prove he were real.

Henry shook his head. He couldn’t get over how much this second son looked like the older Vincent Goosen. “I thought you were his doppelhanger,” he whispered.

“Doppelgänger. I was going to tell you,” Hem said, stepping toward them.

Henry backed up. “You set us up!”

Anna gasped. “You drew that map, didn’t you? And left the poem!”

“And the crowbar.” José’s eyes burned into Hem.

“After I heard those guys talking at the Panthéon, it just … it all came together, and I knew where the painting was. But you got all weird when we stopped to get food, and then Vincent called … and told me you saw him in the park, talking to my mom. I knew you weren’t going to listen to anything I said after that. Unless you didn’t have a choice.” He gestured around the closed-in room and shrugged. “So, yeah. I tricked you to get you here.” He shrugged. “I did what I had to do for the cause.”

Anna narrowed her eyes. “Why didn’t you get the painting yourself?”

Hem laughed a little. “I got busted trying to break in there with some UX guys last summer, so I’m on a list. I can’t walk into the Catacombs like a tourist anymore.”

“But we can.” Henry wanted to punch Hem. “So you used us. You two-faced jerk!”

“Please … try to understand.” Vincent Goosen Junior spoke quietly. He didn’t sound like the same guy who’d barked at Henry, chasing him through the park. “I am the one you should call two-faced — but it is my father and the Serpentine Princes I’ve betrayed. I’ve been in hiding, working for the Silver Jaguar Society for three years now, at great risk to myself. I know more of my father’s secrets than anyone, and —”

“He’s the one who led investigators to the house in Amsterdam,” Hem interrupted, “where Goosen and his other kid got arrested.”

“Why should we believe you?” Henry dug his hands into his pockets.

“You wouldn’t, I suppose. But I am telling the truth.” Vincent Junior stepped to one side, no longer blocking Henry’s path to the door. “Leave if you want. We lured you here — it is true — so you would listen. But now I see the only way to prove we mean well is to let you go.”

“Not yet!” Hem stepped in front of the doorway. “What about the painting?”

Vincent shook his head. “The young man is right. Why should he believe us? Look at them.” He gestured toward Anna and José, still sitting on the bench, blocking Anna’s backpack with their bodies. “In these few days, they have served the society more than many full members do in a lifetime, and they deserve our respect. If they choose not to believe me …” His eyes filled with tears as he looked up to the echoey stone ceiling. “I was not so brave or virtuous in my youth, and it is not within my rights to stand in their way if they wish to protect her on their own.” He motioned for Hem to move. “Stand aside. Trust cannot be forced, only asked.”

The moods on Hem’s face kept changing, but finally, he moved away from the door. His eyes fell on Henry. “There. Go if you want.”

Henry took a step forward, then turned to José and Anna. “Are you coming?”

José looked at Anna, then at Vincent Goosen Junior, and then back at Henry. “Vincent Goosen Senior used to be one of the good guys. If he can change sides, I’d like to think it might work the other way, too,” he said. “I think we should stay and listen.”

Henry shook his head, but he sat down next to Anna and José on the bench. “Fine. Tell us what’s going on.”

Hem and Vincent pulled rusty folding chairs from a corner, sat down opposite the bench in the flickering light, and began. “This room has been a place of resistance for many years,” Vincent said, gesturing around its curved walls. “During World War Two, when the Nazis occupied Paris, members of the Resistance risked their lives, breaking curfew, stealing through the darkened streets and disappearing beneath them to meet in secret. They organized, and planned, and plotted against Hitler’s soldiers from below. They were invisible adversaries, and they helped to liberate the city.”

“I suppose you were there?” Henry scoffed.

“No,” he answered. “But I admire them greatly.”

“That Resistance stuff really happened,” Anna whispered, leaning toward Henry. “We read about it in social studies.”

“It is still happening,” Vincent said. “Good people must take risks to counter the evil in the world.”

“Look at what we’ve already done.” Hem gestured toward the paintings along the bench. “We’ve recovered all but a few of the treasures from the Louvre.”

“Who’s ‘we’?” Henry looked Hem in the eyes. “Anna’s mom? José’s parents? My aunt? Do they even know about him?” He pointed at Vincent. “If they’re part of this, why aren’t they here?”

Hem looked quickly at Vincent and shook his head.

“What?” Henry stood up. “Don’t shake your head at him. You want us to believe your campfire stories? Tell us the truth.”

Hem looked at Vincent again, his mouth a tight line across his face.

Vincent’s face deflated. “They deserve to know.”

“Know what?” Henry wanted to shove them both off their chairs. “What?”

“Sit down,” Vincent said, wiping his brow. “And I will tell you.”

Henry sat. And waited.

Vincent folded his hands beneath his chin and took a deep breath. “My father has them.”

“Your father!” Anna’s face twisted. “Vincent Goosen? He … he has my mom?” Her voice choked on the last word.

“They are unharmed, as best I know,” Vincent said, rubbing his mustache with his thumb. “But he’s holding them … how do you say it? For ransom?”

“Where?” Anna blurted.

“We don’t know.” Hem sighed. “Maybe somewhere in Paris. But the Serpentine Princes also have a château in Auvergne that my mum’s going to check out. She left this afternoon.” He nodded toward Vincent. “That’s what they were talking about in the park.”

Henry narrowed his eyes. “If your mom’s on our side, how come the Serpentine Princes didn’t get her, too? Weren’t they together?”

Hem sighed. “They were. But Mum got away. She was way outnumbered and knew it was best for her to escape and try to find them later.” Hem looked like he felt awful, but Henry wondered if that was real or an act. Hem was the best liar he’d ever met. “That’s what she told me when she called … while you were running around the park.”

Henry crossed his arms. Even if that was true, there were other things that didn’t add up. “If they’re being held for ransom, how come we didn’t get a note or anything?” In Shadow Rogue Assassin, the bad guys always sent a note right away. Otherwise, how were you supposed to know how to get your kidnapped people back?

“We did.” Hem sighed. “Or … they did.” He gestured vaguely up at the ceiling. “It was delivered to a society member’s town house yesterday. With this.” He reached into his pocket and pulled a silver chain from his pocket.

“Mom’s necklace!” Anna lunged from the bench.

Hem handed it to her, and for a few seconds, Anna stared at the polished silver jaguar dangling from the thin chain. It had been passed down through her family for generations, just like the earrings that José’s mother wore. Just like Aunt Lucinda’s silver jaguar charm bracelet.

A candle in the corner flickered and went out, sending up a thin line of smoke.

“So it’s true.” Henry had been hoping it was another lie. He looked at Vincent. “What did the note say? What do they want?”

“The Mona Lisa,” Vincent said solemnly. “Have you hidden it? Or were you unable to —”

Anna started to turn. “We have —”

“Wait!” Henry held up a hand to her. “If you get the painting, will you give it to them?”

Vincent looked at Hem, then stood up and walked over to the smoking candle. “We’ll bring it to the society.” He picked up the candle, tipped it to the side, held its wick to another one, and waited until the flame brightened. He put the candle down and turned back to Henry. “They’ll decide what to do. If we do turn over the painting, it will likely be lost to the world forever, and there is no guarantee —”

“You have to at least try.” José’s voice trembled, and he swiped his eyes with his sleeve. “If we give it to you, you’ll try, right?”

“You have the painting here, then? Where is it?” Hem’s eyes darted around the room.

Anna pulled her backpack into her lap and slid out the rolled-up canvas.

Hem cursed.

“I … I know it got a little smooshed.” Anna’s hands shook as she held it out to them. “We were as careful as we could be, but we had to —”

Hem cursed again and turned to Vincent. “We should have known they’d have a decoy!”

“Decoy?” Henry’s leg was still sore from where the painting had scraped against it. “What do you mean?”

Vincent squeezed his eyes shut and shook his head. Finally, he opened them again. “Leonardo da Vinci did not paint the Mona Lisa on a canvas,” he said. “He painted her on a poplar panel.”

When Anna still looked bewildered, Vincent lifted his hands and outlined a rectangle in the smoky air. “Wood. She was painted on wood. And that” — he pointed to the rolled-up canvas — “is a fake.”

“Then where’s the real one?” Henry’s head was all muddled. “And why would somebody go to all the trouble of leaving us a stupid message with a stupid riddle to find a painting that isn’t even real?”

“Oh, I believe the real painting is there as well.” Vincent let out a fast breath. “If it has not yet been found by someone else.”

“But there was no place else they could have — oh …” Anna’s face fell.

“What is it?” Hem looked at her.

She bit her lip. “There was a space … an open space between the wall and ceiling….”

“That’s it!” Hem looked at his watch. “It’s a little past noon. You’ll have a bit of queue, but you can make it back into the Catacombs before they close for the day.” He stood up as if it were settled. They were going back.

Only Henry wasn’t.

He turned to Anna and José. “Tell me you’re not considering this.”

José looked as if a whole bunch of voices were arguing inside his head. But Anna’s eyes sparked. She held up her mother’s silver jaguar necklace. “We have to, Henry.”

“No, we don’t!” His voice echoed off the stone walls, too loud. But he didn’t care. “We don’t have to do anything he says.” He flung out an arm toward Hem. “He’s been lying to us since we got here. What makes you think he’s telling the truth now? Even if he is, there’s no way I’m going back down there and climbing over all those bones to look for a stupid painting.” The whole idea made Henry’s skin crawl. “Even if we find it, how do you think we’re going to get out of that place with a picture painted on a big hunk of wood? It’s not gonna fit in my pants this time.”

“In your pants?” Vincent’s eyebrows flew up, and he looked as if he might faint. “Oh, dear Lord.”

“So what do you want to do?” Anna glared at Henry. Her eyes pooled with tears, and her voice shook. “You want to leave it there? Leave our parents?

“My parents aren’t here!” Henry shouted. “And I never should have come here either! I’m not going back down there.”

Hem turned to Anna and José, as if Henry had already left. “Will you go?”

Anna looked at José. He nodded. “If a task is once begun, never leave it till it’s done.” José looked up at Henry. “It’s okay if you won’t come. We … we can meet you back home after.”

“Home?” Henry’s voice shook. “That bookstore is not home.” He practically spit the words at José. “Home is Boston. Home is where my dad is.” His voice broke, and his eyes burned with tears, but it didn’t matter anymore. He started for the door.

No one stopped him.