Scrambling out of the sewer, they replaced the manhole cover and snuck out the back of the Emporium. As they entered Base Camp, Darkus saw one of the strings of bottle tops was jangling.

“It’s the Rat Trap!” Bertolt said as Newton flew up to join his cousins on the ceiling.

Virginia ran her finger over the map on the wardrobe. “The one by the wall?”

Bertolt nodded. “What shall we do?”

“If it’s Humphrey or Pickering, we should leave them in there,” Virginia said. “It’ll make moving the mountain easier.”

“It’s probably a fox,” Darkus said, seeing the frightened look on Bertolt’s face.

“There’s only one way to find out,” Virginia said, running back out of the door and falling to her knees.

As they crept toward the Rat Trap, Bertolt whispered, “Surely Humphrey couldn’t get into Furniture Forest. He’s too big. It must be Pickering.”

“If it is, let’s tie him up and tape over his mouth,” Darkus said, thinking about the time he’d spent tied to a chair. Suddenly, Baxter leapt off his shoulder and zoomed forward.

“Shhh.” Virginia put her finger to her lips. They could hear a man struggling and cursing.

Baxter landed and crawled along the top of the Rat Trap, flicking his elytra in the air.

Virginia silently climbed up onto a chest of drawers and peered down into the trap. “Oops!” She clamped her hand over her mouth.

“Who is it?” Bertolt whispered.

“Hello? Is someone there?”

“It’s Uncle Max!” exclaimed Darkus, scrambling up beside Virginia.

“Darkus?” Uncle Max peered up at them. “Is that you? Get me out of here.”

“Oh gosh, Professor Cuttle. I’m so sorry!” Bertolt exclaimed.

“How did you get in there?” Darkus asked.

“I was trying to find you. Ouch! I need to talk to you about . . . Arghhh!” He sucked in his breath. “Blasted things are biting me!”

“We’ll have you out of there in a second, Professor Cuttle,” Virginia said. “Please stop struggling.”

“Stop struggling?! There’s a plague of rats in here!” Uncle Max looked at Darkus. “I saw you three climb over the wall the other day and thought you might have made a den over here, so I came looking for you, which in hindsight was a terrible idea. I’ve been stuck in here for at least an hour!”

Darkus jumped down and helped Bertolt to move aside a mirrored panel and unlock the gate that had swung shut and trapped Uncle Max.

“They’re tame rats,” Bertolt explained, “from a pet shop. You must have frightened them.”

“I frightened them?” Uncle Max pointed to the dead rats hanging down on strings around his face. “What about these poor chaps?”

“I found them in the basement of our block of flats.” Bertolt smiled apologetically. “They were already dead, from poison. I put them in there to scare an intruder.”

“Well, they certainly gave me a turn,” Uncle Max huffed, crawling out of the cage. “They smell awful!”

“I do apologize, Professor Cuttle,” Bertolt stammered. “They weren’t meant for you.”

“Thank heavens!” Uncle Max sat up on his knees and smiled at the worried Bertolt. “Jolly good trap, though—not quite up to Egyptian tomb standards, but nonetheless, pretty impressive.” He looked at the children’s guilty faces. “So, is someone going to tell me what’s going on here, or do I have to guess?”

Virginia nudged Darkus, who was staring at the floor.

“Your neck’s bleeding!” Uncle Max took Darkus by his shoulders.

“It’s fine. I had a splinter,” Darkus replied, covering the cut on his neck with his hand.

“Er, would you like to come back to our camp for a cup of tea, Professor Cuttle?” Bertolt asked politely. “It might soothe your nerves, and we can explain everything there.”

“A camp, eh?” Uncle Max straightened his safari hat. “Don’t mind if I do.”

They set off through the tunnels on their hands and knees, Baxter flying in front, leading the way. “This place is a rabbit warren!” Uncle Max exclaimed as they inched forward. “It’s a good job archaeologists are used to confined spaces.”

“I’m sorry, Professor Cuttle, but we need to be quiet,” Virginia whispered. “We don’t know when Pickering and Humphrey will get back.”

“Apologies!” Uncle Max whispered back. “Understood.”

As they all filed through the door of Base Camp, Uncle Max whistled in amazement at the throbbing glow of fireflies reflected in the chandelier crystals dangling from the ceiling.

“This is quite a setup you’ve got here,” he remarked as Bertolt plugged an electric kettle into the car battery.

“Most of this stuff was already here,” Darkus said.

“Apart from the kettle,” Virginia added. “That’s Bertolt’s.”

Uncle Max gazed up at the ceiling in wonder. “Where have all these beetles come from?”

Darkus looked at Virginia but didn’t reply. Baxter settled on his shoulder.

Uncle Max saw the map on the back of the wardrobe and wandered over, inspecting the collection of images around the words LUCRETIA CUTTER. He touched the edge of Novak’s card.

“Do you take milk or sugar?” Bertolt asked.

“Black, six sugars, thank you, Bertolt.” Uncle Max turned to face Darkus, his voice suddenly serious. “I think you’d better tell me exactly what’s going on here, lad. Don’t you?”

Darkus, Virginia, and Bertolt looked at one another.

“And no flimflam, please.” Uncle Max took his cup of tea from Bertolt and sat down on the sofa. “I want the truth.”

There was an awkward silence, in which Uncle Max took a mouthful of tea.

“I’ve found Dad,” Darkus said.

Uncle Max sprayed his tea across the table. “WHAT?!” he spluttered.

“Lucretia Cutter has him in a cell, in the basement of her house,” Darkus said hurriedly.

“How can you know that?” Uncle Max was on his feet. “By Jupiter, please tell me that you haven’t been there!” His face was flushed purple, and his eyes were bulging out of their sockets.

Darkus looked guiltily at Virginia and Bertolt, then nodded.

“DID SHE SEE YOU?”

Darkus nodded again, wondering if Uncle Max was about to have a heart attack. “She shot at me, but she missed,” he said. “That’s how I got the splinter.”

“She shot at you?” Uncle Max paused, then dropped back down onto the sofa and picked up his tea. “Well, that’s a relief.”

“What?!” Bertolt spluttered. “Why is that good?”

“Because it means she doesn’t know who he is,” Uncle Max explained. “If Lucretia Cutter had recognized Darkus, she wouldn’t have shot at him—she’d have kidnapped him and used him against Barty.” Uncle Max shook his head. “I can’t believe you’d be so stupid as to go into that Gorgon’s house! You could have gotten yourself killed, and your father, too.”

“What’s a Gorgon?” Virginia whispered to Bertolt.

“A monster-woman who turns men to stone by looking at them,” he replied under his breath.

Darkus felt like he’d been slapped in the face. When he’d gone to Towering Heights, he hadn’t meant to put himself or Dad at risk. How could he, when he didn’t even know Dad was there? Then another thought occurred to him.

“You knew she had him all along!” he gasped.

“No! At least, not until we went to the museum—and even then, I had no real evidence.” Uncle Max shook his head. “Her name over the door, that yellow ladybug, and her sudden arrival—these things are not enough to accuse someone of kidnapping.” He sighed. “I’ve been trying to find out where she’s keeping him. I thought he might be in her cosmetics factory in Wapping.” He blinked. “I tried her offices, and her string of warehouses on the Thames, but with no luck.”

“How?” Darkus asked. “When?”

“I haven’t been going to work,” Uncle Max admitted, “and you may not believe this, but I do a rather convincing impersonation of a confused delivery man.” He smiled. “I’ve got a blue jumpsuit, a badge, and a cardboard box. I wander into a building, looking lost, and start asking questions. People can be astonishingly helpful, you know.” He tugged on his earlobe. “I must admit, it didn’t occur to me that she’d have him at her house. The nerve! She must be very confident she won’t get caught.”

“But why didn’t you tell me?” Darkus asked angrily.

“Darkus, I didn’t have any proof that Lucretia Cutter had Barty, just a hunch. I was looking for evidence.”

Darkus glared at his uncle.

“But today I thought I should pursue a different line of inquiry. Instead of trying to find out where Lucretia Cutter has Barty, I decided to try and find out why she has him, and that’s why I came looking for you. I need to talk to you about your friend.” He pointed at Baxter. “I need to know more about your beetles.” He lifted his hands up, gesturing to the fireflies.

Darkus wasn’t listening. He was so angry his whole body was shaking. “You’ve been keeping secrets from me.”

“No, Darkus, I haven’t,” Uncle Max said softly. “I wanted to be sure of the facts before I told you anything that might get your hopes up. Barty is in grave danger.” Darkus struggled with what he was hearing. “I’m here now, aren’t I?”

Darkus nodded, his teeth clenched.

“What about you?” Uncle Max raised an eyebrow. “Haven’t you been keeping a few secrets of your own?”

Darkus looked at the floor. “I didn’t tell you the whole truth about how I found Baxter,” he admitted. “I thought you’d make me give him back.”

“Well, how about you tell me now?”

Bertolt set about making more tea while Darkus told his uncle about Baxter falling out of Humphrey’s trouser leg, discovering Beetle Mountain, and being kidnapped by the neighbors and then rescued by the beetles. Virginia described Darkus taking them to Beetle Mountain, and the oath they had sworn to help him rescue his father and protect the special insects.

Uncle Max sat, listening intently.

“If I wasn’t seeing this with my own eyes, I’d never believe it,” he muttered, looking up at the ceiling and shaking his head. “But none of this explains why you went to Lucretia Cutter’s house.”

“Lucretia Cutter visited Humphrey and Pickering last week,” Virginia explained, “on the night they kidnapped Darkus.”

“Novak Cutter saw me looking out of the window and dropped that card.” Darkus pointed at it.

“Lucretia Cutter was here?” Uncle Max recoiled.

Darkus nodded. “She’s buying the beetles.”

“Over my dead body she is,” Uncle Max growled.

Virginia looked at him, surprised.

“That’s why I went to her house—to find out why she wants them—but also”—Darkus paused—“also to find out whatever it is about her and Dad that you won’t tell me.”

Uncle Max’s eyebrows shot up. “I see.”

“Now it’s your turn to tell the truth,” Darkus said, thinking about the photograph on Lucretia Cutter’s desk. “What’s the Fabre Project?”

Uncle Max lifted his safari hat, smoothed down his hair, and replaced it, looking at Darkus as if measuring him in some way. “I made a solemn promise to your father, when you were born, that I would never speak of the Fabre Project to you—or anyone else, for that matter.” He scratched his chin. “But then, we never knew we’d find ourselves here, did we?”

Darkus stared at his uncle. “I thought it was you keeping something from me—that you didn’t trust me.” He turned away. “But all along, Dad’s been the one keeping secrets.”

“Your dad trusts you, lad,” Uncle Max said. “It’s just . . . well, there are some things that the young shouldn’t be burdened with.”

“When Dad disappeared, people said terrible things about him.” Darkus’s voice was flat and unemotional. “But I kept his face here.” He tapped a finger between his eyes. “Each time someone said that he’d run away—or, worse, that he’d killed himself—I knew they were wrong here,” he touched his fist to his heart, “because my dad would never do that. My dad isn’t like that.” He looked up at his uncle, his vision blurred by tears. “But I don’t know what my dad is really like, do I? I don’t know him at all.”

“Nonsense. Look at me, lad.” Uncle Max took Darkus’s hand. “You know your father better than anyone. But before he was your dad, he was a young man with ambition, and without the responsibility of a family. That young man was like you in many ways, and he was a great adventurer. That’s something you should be proud to learn.”

“An adventurer? Like you?”

“No, no. I search for secrets, dig for truths, and if I’m lucky, I’ll find an interesting story, or a valuable object.” Uncle Max sighed. “Your father’s adventures were far greater than any of mine, and more dangerous. His adventures were in thought. He explored the very fabric of nature, experimented with possibility, and all within the confines of his own head. You can only do that sort of thing if you have a brilliant mind, and he does. Mine’s rather ordinary by comparison. Your father, Darkus, is the kind of person who changes history.”

“That doesn’t sound like Dad.” Darkus frowned. His father was gentle and liked staring out of windows; he would never describe him as an adventurer.

“That’s because he stopped his adventures when you came along.”

“But why?”

“Adventures are dangerous, Darkus, and villains are real.” Uncle Max seemed to grow older as he spoke. “Ideas are powerful, and there are people who’ll exploit even the most charitable idea for power, or money. The greedy stop at nothing to satisfy their appetites, with no thought to the devastation or destruction it causes.” He sounded angry. “That’s not a world in which your father wanted to raise a family.”

“Dad gave it up to have me?”

“In a manner of speaking.” Uncle Max rested his chin on his hands. “Barty was an entomologist, a genius with arthropods. He specialized in Coleoptera; beetles were his passion. And because of his great skill in observing and understanding insects, Professor Appleyard invited him to be one of the esteemed scientists working on the Fabre Project.”

“An entomologist?”

Uncle Max nodded. “The Fabre Project had a bold mission: to see if it was possible to reverse the damage humans have done to the planet by harnessing the power of insects.”

“The power of insects?” Bertolt whispered in awe. “Is that possible?”

“The sad fact is, the number of insects is in decline. As we destroy their habitats, so we destroy their species, but we desperately need them. If all the mammals on the planet were to die out, the planet would flourish—but if all the insects disappeared, everything would very soon be dead.

“Led by Professor Appleyard, the Fabre Project explored the possibility of setting up global insect farms to breed species of insect that would boost pollination, naturally control pests—cutting down the use of pesticides—provide humans with food, and deal with human and animal waste.”

“The dung division.” Virginia sniggered.

“Esme was part of that team. That’s how your father met her.”

“Mum was a scientist?” Darkus was flabbergasted.

“She was a mighty fine ecologist,” Uncle Max said. He shook his head with a sad smile. “Your father was working with a geneticist to see what could be achieved by tampering with the genetic makeup of beetles.”

“Lucretia Cutter,” Darkus spat.

“She was plain old Dr. Lucy Johnstone back then. An odd girl, if I’m honest, but very clever and fiercely ambitious. She and Barty had a major breakthrough with their transgenic experiments on certain types of beetles.”

“Transgenic?” Virginia frowned. “What does that mean?”

“It means changing the genetic structure of an organism by adding genes from another organism. They took genes from mice and successfully added them to the genes of a beetle.”

“A beetle-mouse?” Virginia laughed. “I don’t get it—what’s so amazing about a beetle-mouse?”

“The first transgenic experiments used genes from mice . . .” Uncle Max paused for an uncomfortably long time. “But the aim—the true aim—was to find a transgenic process that would successfully transfer human genes into beetles, producing a new species of beetle capable of intelligent thought, to work collaboratively with humans and clean up the environment.”

“Beetles with a human gene!” Darkus looked at Baxter perched on his shoulder.

“Did they do it?” Virginia sat up, staring at Newton bobbing about above Bertolt’s head. “Did they discover the trans-thingy process?”

Uncle Max sighed, looking at Baxter. “I’ve seen a beetle behave like Baxter before, when your father was still working on the Fabre Project, and it was carrying his genes.”

“Our beetles are transgenic!” Bertolt looked up at Newton, smiling in wonder.

Darkus studied Baxter. “Was Dad’s beetle a rhinoceros beetle, too?”

“It was a Goliath beetle, and he was a majestic beast.”

Darkus thought about the zebra-striped beetle he’d met on Beetle Mountain. “What happened to it?”

“Barty had Goliath frozen and donated him to the Natural History Museum’s collection for future research.”

Darkus blinked. He was certain that if they looked, they would find Dad’s beetle gone.

“What happened to the Fabre Project?” Virginia asked.

“When they started having successful results, Lucy tried to persuade Barty to leave the project and set up their own laboratory. She believed their work would make them rich.”

“She didn’t want to help the planet?” Bertolt asked, dismayed.

“But she’s got loads of money,” Virginia said.

“Yes, she has now,” Uncle Max agreed.

“Dad refused,” Darkus said with certainty.

Uncle Max nodded. “Realizing what her motives were, Barty destroyed all their research and handed his resignation to Professor Appleyard, explaining what Lucy was planning. Outraged and furious, Lucy Johnstone disappeared, emerging several years later under a new name—Lucretia Cutter. Without the genetics work, the Fabre Project floundered and it was closed down.”

“Darkus’s dad destroyed his research!” Bertolt said.

“But he didn’t—did he, Uncle Max?” Darkus stared at his uncle. “It’s upstairs, in your flat.” He’d remembered where he’d seen the words Fabre Project. “The box that ripped open, with Nefertiti’s teeth in it—it was full of folders that said ‘Fabre Project’ on the side.”

Uncle Max looked gray. “I didn’t want to take it. I’m not a fan of mucking about with nature. I’m a man of the Old World, and I didn’t approve of what your father was doing. I felt he was opening Pandora’s box. In fact, we almost fell out about it. Barty promised your mother he’d burn the research, but he couldn’t bring himself to destroy his life’s work, so I agreed to keep it on the condition that he never meddle with it again. It’s been sitting in my box room for years. I’d forgotten it was there, until you came to stay.”

“Lucretia Cutter said that the beetles belonged to her,” Virginia said.

Uncle Max frowned. “It was only a matter of time before she found a way to complete the human-beetle transgenic process on her own.”

“This is serious, isn’t it?” Darkus said.

“Very,” Uncle Max replied gravely. “Beetles are the single most successful species of creature on this planet. They can adapt to almost any environment. The question your father was trying to answer was what happens if you genetically enhance the most adaptable creature on the planet? I thought that was the most dangerous question I had ever heard.”

“But Lucretia Cutter also said that she wasn’t ready yet,” Darkus said, remembering what she’d said in the room with the two-way mirror, “and that she wouldn’t let anyone stop her—not them, not him, nobody . . . I think Dad was trying to stop her.”

“I’ve been trying to find out what she’s up to, but every avenue I’ve explored turns up a blank. It’s impossible to investigate her. No one will speak about her. They’re all petrified.” Uncle Max shook his head. “However, I am certain of one thing. Whatever she’s up to, we have to do everything in our power to stop her.”

“We’ve got to tell the police,” Bertolt said.

“The police are astonishingly uninterested in investigating any of the leads I have provided them with.”

“But why?” Bertolt asked.

“Because someone is exerting their power and making sure that Barty’s disappearance is not looked into.”

“Lucretia Cutter,” Virginia snarled.

“And if she thought that we knew where Barty was, she’d move him immediately, and we’d never find him,” Uncle Max said. “So we have to tread very carefully. We can’t trust anyone but one another.”

Darkus looked at Virginia and Bertolt. “We have a plan to rescue Dad.”

“Really?” Uncle Max smiled. “I hoped you might. Care to share it with me?”

Baxter rose up from his perch on Darkus’s shoulder and hovered beside the boy’s face, his elytra lifted high, his soft wings vibrating like a hummingbird’s.

“We’d love to,” said Darkus.

“But first, I need to go home and get two bottles of champagne,” Bertolt said, climbing to his feet.

Darkus smiled at his uncle’s surprised expression. “It’s all part of the plan.”