Max watched the blue dot race across the sand.

“Come on, we don’t have much time!” Sasha clapped him on the back. “Let’s grab the Blues and get them downstairs!”

Max didn’t answer. He was thinking about something Mr. Darrow had said to him once.

The janitor had been fixing his latest model: a scale replica of Buckingham Palace, with 775 rooms and seventy-eight working toilets. It had taken him a whole year to build, but now he was taking it apart again. He’d discovered a mistake in his calculations, and one of the bedroom walls was a millimeter off.

“Why bother?” said Max. “It’s only a millimeter!”

Mr. Darrow looked at him through the microscope goggles. Beneath the glass lenses, his eyes were magnified to fat black beetles.

“Do you like poetry, Max?”

Max thought about it. “Er…I think so.”

“Well, I don’t,” said Mr. Darrow. “It’s just writing with bits missing. Laziness, if you ask me.” He leaned over the palace with a pair of tweezers. “But there’s one poem I do like:

‘To see the world in a grain of sand,

And heaven in a wild flower,

Hold infinity in the palm of your hand

And eternity in an hour…’ ”

Max frowned. “What does that mean?”

Mr. Darrow took hold of the faulty wall.

“It means you have to find beauty in the smallest things—because small things are important. If you don’t take care of them, they come back to bite you.”

He pulled out the faulty wall…and the whole palace collapsed. He held up the tiny piece of wood. It was no bigger than a splinter, but it had held everything together.

“Never forget that, Max,” he said. “A millimeter matters.”

Max watched as Luke disappeared across the floor. Just like the single piece of wood in Mr. Darrow’s model, everything relied on him now. If he didn’t succeed in making peace with the Reds and Greens, then there was no way that Max’s plan would work.

Sasha stepped toward the bin, but once again Max stopped him.

“No! Not so fast!”

Sasha blinked. “Why not?”

“Because we have to get this perfect.” He held out his arms to the room. “Look around you—all this started because of one squashed fly!”

Sasha looked guilty. “I told you, that was an accident….”

“Of course it was!” said Max. “But we can’t let anything else go wrong now—we have to make sure we do this without anyone getting hurt.”

Sasha gulped. “How are we going to free the Blues without hurting any Greens?”

They looked at the crowd of Blues outside the Bin. The Greens had already put them to work constructing a giant papier-mâché monument of the Bin King from old newspaper. Green soldiers on warflies were whipping the Blues with strands of dental floss.

“We have to get the Greens to leave,” said Max. “But no scaring them! They all think we’re monsters, so we have to show them we’re not!”

Max picked up the shovel and the two boys carefully crept toward the Bin, checking with every footstep to make sure they didn’t accidentally squash anyone.

“That’s it, nice and slow,” said Max. “Show the Greens that we’re not here to hurt them and—”

Max stopped. The Greens had already panicked and shot inside the Bin, barricading the entrance with two empty crisp packets. The imprisoned Blues were left stranded on the sand, staring up at Max and Sasha in terror.

“Never mind,” said Max. “Let’s just grab them.”

He pulled on the goggles and crouched in front of the Blues, who were cowering and begging for their lives.

“Don’t be afraid!” said Max. “I’m not going to hurt you—just stay still!”

He carefully dug the shovel into the sand beneath the Blues and then lifted it as slowly as he could. It was trickier than Max had expected—he was petrified that at any moment the Blues would panic, charge off the shovel and fall to their deaths—but when he finally stood up, he was relieved to see it had gone perfectly. The Blues stood safe and sound in the middle of the shovel.

“Quick! The tray!”

Sasha held out the seedling tray, and Max deposited the sand inside. Ten thousand Blues tumbled across the plastic and squeaked in panic, but it looked like no one was hurt. Max breathed a sigh of relief and carried the tray to the desk.

“Right, almost done!” he said. “Bring me the castle and I’ll get it fixed.”

Sasha raised an eyebrow. “Fix the castle? Why?”

“The Blues need somewhere to live, remember?” said Max. “It’s not big enough, but it’s better than nothing. I’ve got to make sure the castle is safe—they could trip on the broken staircases, or get skewered on splinters or crushed by falling roof beams, or—”

“All right, all right,” Sasha grumbled. “Just be quick—we’re running out of time!”

Max carried the castle to the desk and pulled off the base with a set of Mr. Darrow’s precision tweezers. Malcom was no longer anywhere to be seen, but Max could see all the damage done in the battle. There were doors broken in, and tiny scuff marks on the walls from miniature sword fights. Sasha tapped him on the shoulder.

“Max, you made that?”

Max nodded.

“I had no idea you were so good!” Sasha shook his head in amazement. “Why didn’t you tell me?”

Max tried not to blush, and failed. “I thought you’d think making models was, you know…stupid.”

“Are you kidding? I could never make anything as good as that!”

Max shrugged. “So? You’re good at talking to people—I’d give anything to do that.”

Sasha handed him the glue, and Max started fixing the broken doors.

“You know, Max, you’re too hard on yourself,” said Sasha. “You should try talking to people more.”

Max shook his head. “I’m no good with people.”

“You’re good with me.”

Max snorted. “Yeah, but you’re easy to talk to! Most people aren’t. Can you pass me the tweezers?”

Sasha handed them over. “You can’t be on your own all the time. Why don’t you start a model-making club here? Show people what you can do—I bet loads of kids would want to learn.”

Max shook his head.

“It’s a nice idea, but it’s not for me. Half the time I’ve got no idea what people are saying. That’s why I’ve always loved models, you know? You don’t have to struggle to understand models. They just are.”

He put the base back on the castle and started filling the holes in the walls.

“I guess I’ve never had much control over anything in my life. But when I’m making models, I’m in charge—even if it’s just for a short while. It feels good. In fact, it’s the only thing I’ve ever been good at.”

He fixed the turrets on the towers so each one stood up straight.

“That’s why we have to get this perfect. This is my chance to show Mr. Darrow I’m good enough to look after his work for him. After this, who knows…maybe we can start up a business or something. Me and him, making living models together.”

Max put the castle on the desk and admired it. It was already as good as new.

“There!” He dusted off his hands. “Now let’s get these Blues downstairs, before—”

“Max!”

Sasha was frantically waving at him, pointing at the tray in horror.

“The flies!”

Max gasped. Hundreds of warflies were pouring from the bin behind him and landing on the tray. Green soldiers were grabbing as many Blues as they could, dragging them onto the flies and carrying them away by the dozen.

“They’re taking the Blues!” Max cried. “Stop them!”

Sasha ran in front of the bin, blocking a swarm of flies as they tried to reenter it—and leapt back.

“Ow! They just stung me!”

“Stung you? How could a fly—”

Max felt a sudden sharp pain on his cheek and yelped. One of the warflies circled his head. With the goggles, Max could see Green soldiers on its back loading up their catapults with tiny staples broken into razor-sharp fragments.

“They’re—ow!—firing at us!” said Max.

“You think?” cried Sasha, swatting flies left and right. “Go away! Shove it, you stupid little—”

“No!” cried Max. “There are—ow!—people riding them, remember? You can’t hurt them! Keep blocking the bin and I’ll—ow!—save the Blues!”

He reached down to scoop the rest of the Blues from the tray, but he was too late. The Blues didn’t want to be saved—they were running from him. Some were even climbing onto the warflies to escape, hugging the Green captors and crying with relief as they were carried away.

“No! What are you doing?” said Max. “Don’t go with the Greens—they’re the enemy! I’m trying to save you!”

It was no good—the Blues didn’t understand. Within seconds they had fled the tray, and a swarm of warflies surrounded Max and Sasha, flinging round after round of catapult fire at their faces.

“Max! What do we do?”

Max gazed around the room in horror. Mr. Darrow’s creation was even less like a model than he’d thought. It couldn’t be controlled at all. It fought back.

There was only one thing to do now.

“RUUUUN!”

Max and Sasha leapt out the door, slamming it behind them. They stood in the corridor, gasping for breath.

“That went well,” said Sasha.

His face was covered with so many swollen marks it looked like he’d nose-dived in a bowl of red jelly beans.

“Right, forget being nice!” he said, rolling up his sleeves. “Let’s go back in there and show those Greens what we’re made of!”

Max held him back. “No! We can’t hurt them!”

“Why not? They’re hurting us!”

“Because it’s Mr. Darrow’s creation, remember? We can’t damage it—not even one person! Mr. Darrow always used to tell me that even the smallest things matter: you take your attention away for one second, and before you know it, they—”

Max stopped. He had noticed something from the corner of one eye.

Joy and the Sparkle Pony Summer Club were standing at the top of the stairs, staring at them.

“J-Joy!” cried Sasha. “What are you doing up here? I told you not to leave the games room!”

Joy was surprised. “We came to look for you. You said you’d be gone only a little while….”

“Well, we’re done now!” said Sasha. “Get downstairs, before Mr. Pitt—”

“What were you doing in Mr. Darrow’s room?”

Max and Sasha froze.

“Wh-what?” said Max.

“We just saw you come out of Mr. Darrow’s room,” said Joy.

Max and Sasha shared a terrified glance.

“We weren’t doing anything!” said Sasha. “So don’t tell anyone, OK? Especially not Mr. Pitt!”

Max winced—Sasha had already said too much. Joy’s eyes lit up. A smile tweaked at the corner of her mouth.

“Soooo…you’re saying that if Mr. Pitt found out, you two would be in trouble?”

Sasha nodded. “Yes! Lots of trouble!”

Joy walked toward them, playing with her pigtails innocently. “Soooo…if we decided to tell him, then you two would be expelled?”

Sasha’s face turned white as he realized what was happening. All the girls were walking toward them now, smiling.

“Joy, please! This is important—you have to believe me!”

Joy shook her head sadly. “But how can I believe you, Sasha? You said you’d spend the whole day with me, but you didn’t….You said we’d make friendship bracelets and do dance routines and watch The Sparkle Pony Movie, and we haven’t done any of those things….”

“We will!” said Sasha. “Max and I will do anything you want!”

Joy stopped—it was exactly what she had been waiting for. She turned to the girls behind her, and they grinned like a shoal of piranhas. Max suddenly felt very, very frightened.

“Anything?” said Joy.