Jake had never loved his backpack more than he did that morning. It had not one, not two, but three secret pockets inside. There was more than enough room for Miss Earhart and Sir Isaac to spread out, get comfortable, and relax until the school day ended. To be on the safe side, Jake decided to travel light, leaving his lunch and school books at home. Hot lunch was gross, but it was worth eating it if he didn’t have to worry about his tiny geniuses being crushed by a cookie or smushed under a sandwich.

About a block away from Franklin Elementary School, Jake peeked into his backpack to check on them. He grinned when he saw each one hard at work building a miniscule component of the plane’s engine. Hopefully, their tasks would keep them busy—and out of trouble—for the rest of the day.

“Now, listen,” Jake said for the umpteenth time, “you guys have got to stay in my backpack until we get home. All day. No exceptions. If anybody sees you—”

“I assure you, boy, I have no interest in wasting my day at your school,” Sir Isaac interrupted, not even bothering to look up from the electrode in his hands. “My own school days were tedious enough.”

“We’re here to help you, Jake, not make more problems!” Miss Earhart said brightly. Jake tried to return her smile. We just have to get through the science fair on Friday, Jake reminded himself. One more day.

“Okay,” Jake said in a low voice. “Let’s go.”

When Jake arrived in Ms. Turner’s classroom, the clock read 8:29:54:12. He was less than six seconds away from getting a tardy! Jake slid into his seat right before the bell rang.

“Safe!” Ms. Turner joked, spreading her arms like an umpire. The whole class laughed, and even Jake smiled as he carefully tucked his backpack under the desk.

“Books closed. Papers out. Pencils up,” Ms. Turner announced.

Jake’s smile disappeared. Those were the worst six words to hear first thing in the morning. They meant Ms. Turner was going to give a pop quiz.

“Since the science fair is tomorrow, we’re going to review the key terms for your projects,” the teacher continued. “If the judges ask you to explain a term, you’ll need to be ready. When I say each word, please write down the definition.”

Jake’s face scrunched into a worried frown. He’d been totally stumped when he saw the science-fair words on the instructions. All those times he’d waved the instructions at Sir Isaac instead of reading them—

Jake closed his eyes. He could picture the instructions in Sir Isaac and Miss Earhart’s workshop under his bed. If only he could remember what they said!

“‘Hypothesis,’” Ms. Turner announced.

Jake tried to think. Was it H-I-P or H-Y-P? He glanced at the red numbers on the clock, a blur as the milliseconds slipped away …

“‘Hypothesis,’” repeated Ms. Turner.

Hipothesis, Jake scribbled. Then he frowned. It didn’t look right. Without even bothering to erase, he quickly changed the first “I” to a “Y.” But spelling “hypothesis” wasn’t even the hardest part. Now he had to define it.

Jake gnawed on the end of his pencil. A hypothesis is a kind of guess, he wrote. A guess that scientists make about something they think will happen.

Jake stared at his answer, trying to think of something else to write. He heard everybody else’s pencils scratching, scratching …

And then he heard something else.

Z-z-z-z-z-z—zip.

Jake froze.

That sound—it was coming from under his desk.

It was coming from his backpack!

No, Jake thought desperately. No, no, no, no!

There was only one possible explanation for why his backpack would unzip itself.

Sir Isaac and Miss Earhart were trying to escape!

What am I going to do? Jake wondered, trying not to panic.

But the whole class was in the middle of taking a quiz. He couldn’t exactly start talking to his backpack without attracting attention.

“The next word is ‘procedure,’” Ms. Turner announced.

Jake’s fidgety hand jerked forward. It bumped his pencil and sent it clattering to the floor—right under his desk. Luckily, Ms. Turner noticed. She nodded at Jake so that he knew he had permission to get it.

Jake dove under his desk. His backpack was already unzipped two inches! He stuck his face near the opening and hissed, “What are you doing?”

“We need air,” Sir Isaac said with a scowl. “It is oppressively hot in here. And this satchel of yours carries the distinct odor of—”

“Feet.” Miss Earhart spoke up.

“Just deal with it,” Jake said through gritted teeth. “Stay put—and no more unzipping.”

With a fast tug on the zipper, Jake returned to his seat. He started scribbling pro—

Zzzzzzzzzzip!

Not again, Jake thought. With his foot, he tried to move his backpack under the chair.

Across the aisle, Aiden glanced at Jake and frowned. Jake stared hard at his paper. He wasn’t even finished writing “procedure” when Ms. Turner announced the next word. “‘Investigation.’”

Jake knew that he had no choice but to move on. He shifted his feet to push the backpack again. The buckles on the straps clacked against the tile floor.

“Ms. Turner!” Aiden’s hand shot into the air.

Everyone turned to look at him. Jake slouched low in his seat, wishing he could use mind control to keep Sir Isaac and Miss Earhart in his backpack.

“Yes, Aiden?” Ms. Turner asked. “Is there a problem?”

“Jake’s fidgeting and it’s really distracting,” Aiden replied.

“I am not!” Jake protested.

A pinched look crossed Ms. Turner’s face. “Aiden, keep your eyes on your own paper and you won’t notice any distractions,” she replied. “Now, back to the quiz. The next word is ‘process.’”

Luckily, there were only two more words after “process.” At last, Ms. Turner announced, “Please pass your papers forward.”

Jake passed his quiz to the person who sat in front of him. Another F, he was sure … and Jake had a terrible feeling that his day was only going to get worse.