I appreciate the many qualities Dr. X gave me.

I appreciate even more that he kept his humanity to himself.

—Three, Personal Log

“Ms. Snapper?” said Trevor Weiss, his skinny arm swaying in the air like a riverbank reed in a mild breeze.

Fisher and Alex shot each other a curious look.

First-period biology was no more than a post-breakfast nap for most of their classmates. Ms. Snapper had gotten used to the slumped bodies, the blank eyes, and the background murmur of soft, slow breathing since taking over for Mr. Granger. Fisher and Alex, usually the only students awake enough to answer questions, had been looking forward to joining in the group snooze for once. They were both tired from working in their parents’ labs the night before, carefully analyzing the dirt samples they had withdrawn from the duck suit.

But this morning was different. Kids were shifting in their seats, exchanging unpleasant glances with one another. Paper airplanes were under construction beneath several desks.

Even Amanda seemed oddly fidgety. Fisher nodded in her direction and raised an eyebrow at Alex, but Alex shrugged and shook his head only. Veronica had purposefully sat in the farthest corner of the room from Fisher, but he didn’t need to question what she was annoyed about. He’d tried to catch her eye once or twice, with no success. Her last words still rung in his ears like she’d carved them in with a mallet and chisel.

“What is it, Trevor?” Ms. Snapper said, a harsh edge to her voice. Fisher didn’t know if she’d had a bad morning or maybe had decaf to drink by accident, but she wasn’t in much of a mood for questions.

“I’m afraid I misplaced my handout on photosynthesis,” Trevor said with his customary delicacy. “Could I have another one, please?”

Ms. Snapper took in a breath and let it out very, very slowly.

“Of course,” she said, as if Trevor had just asked her to handwrite the study sheet in hieroglyphics. She took several labored steps from the blackboard to her desk and pushed around a paper pile. When her attention was on her desk, a paper plane sailed through the air. Its intended target, a girl in the first row, moved her head at the right moment, and the plane glided to a stop smack in the middle of Ms. Snapper’s desk.

She snatched up the offending object. Taking a quick look around the room for the perpetrator, she pulled her arm back like a major league pitcher and sent the plane on a spiraling kamikaze flight. Several kids had to duck before its nose crumpled against the back wall.

“That’s it!” she snapped. “Everyone, take out a blank piece of paper.”

Spooked by Ms. Snapper’s uncharacteristically angry reaction, everyone obeyed.

“Since you’re content with spending the class period wasting my time, today, I’m going to waste yours. I want you to write the names of every sitcom character you can think of in reverse alphabetical order.” A kid raised her hand. Ms. Snapper looked at her. “And if your question for me is why, then you’ve really missed the point.” The student put her hand back down.

Fisher and Alex looked at each other. Everyone in the class started writing away as Ms. Snapper’s narrowed eyes kept watch. Fisher and Alex shrugged, sighed, and joined in.

The rest of the class period was spent in solemn silence. Fisher was having trouble coming up with more than twelve names.

“Time’s up,” Ms. Snapper said suddenly, and most of the class jerked reflexively at her sudden, loud voice. “I expect you to come in tomorrow and focus. Clear?”

Everyone nodded.

“Good. Go.”

The class filed out silently. Their aggressive whispering and rowdiness resumed only when they reached the safety of the hallway.

“What was that?” Fisher said, exhaling. “I’ve never seen everyone so riled up.”

“I have no idea,” Alex replied, “but I think it’s spreading.”

As other classes spilled into the hallways, it became apparent that the plague of bad moods had spread across the entire school population. Kids pushed and shoved and tripped one another with more than normal frequency. Friends broke into heated arguments about subjects even less important than usual. Fisher spotted at least five notes taped to people’s backs, with everything from KICK ME to PUSH ME to the more creative DROP ME INTO A SHARK TANK.

“Maybe it’ll pass,” Fisher said.

“Yeah …,” Alex said, uncertainly. “Maybe.”

Fisher’s second and third period teachers were grumpy, too, but they were always grumpy, so it was difficult to tell if anything was out of the ordinary. He decided things were improving.

Until fourth-period English.

Spitballs flew around whenever Mrs. Weedle’s back was turned, and little shoving matches broke out between kids at neighboring desks.

Nobody raised their hands, and those who got called on gave totally wrong answers. At last, Mrs. Weedle had enough.

“I try and try and try,” she said, her old, breathy voice straining to its upper heights. “But I cannot push the importance of symbolism into your tiny adolescent heads!”

“I dunno,” said Jake Talbot, a skinny blond boy in an orange T-shirt. “I don’t think it’s always such a big deal for something to represent something else. I mean”—he gestured to the wastebasket in the corner—“why can’t the trash can just be a trash can sometimes?”

“Just a trash can,” Weedle repeated, walking over to it. “Just a trash can.” She picked it up. “Here’s a symbol for you. This trash can is full of crumpled papers and represents all of the foolish ideas in your head.” Whispers raced around the classroom and Fisher tensed at his desk. Mrs. Weedle was usually such a kind, dull, soft-spoken old woman. Fisher had never seen her express much of any emotion, least of all anger.

“As long as you keep learning and studying, most of those thoughts will be cleared away.” She paced toward Jake Talbot, still clutching the wastebasket. “But what happens if you stop thinking critically? If you don’t learn from your mistakes?”

With that, she flipped the wastebasket upside down and shook it rapidly over Jake’s head, releasing a clattering cascade of old homework, quizzes, paper cups, pencil shavings, and other odds and ends all over the bewildered student and his desk. Jake swatted at the garbage like it was a cloud of horseflies, and fell out of his chair. Other kids jumped to their feet, shouting and laughing. Fisher, stunned, was glued to his desk. The class was in an uproar.

“Now think about that!” Weedle practically screeched. “And be gone!” She flung her arm up toward the ceiling, nearly shattering a lightbulb.

As Fisher left the classroom, Alex was getting out of his history class next door. Fisher grabbed him by the arm as soon as he saw him.

“It’s worse,” Alex said.

“I don’t understand it,” Fisher said. “What could put the entire school in such a bad mood at the same time? And why aren’t we affected?”

“We need more data,” Alex said just as the Vikings tore around a corner, heading right for them. He grabbed Fisher’s arm. “Oops. Viking alert.”

They started to duck back into Alex’s history classroom, but Willard completely ignored them and kept right on running.

“I d-didn’t know that those were your ham sandwiches, Leroy!” he shouted as he ran. “I’m s-sorry for eating them!”

“You’ll stew the hay when you messed with my ham!” Leroy said, chasing Willard.

“Rue the day! He’ll rue the day!” said Brody, tearing after them.

Fisher and Alex looked at each other, wide eyed. Alex shrugged.

The brothers walked down the hall cautiously, staying on the alert. They hadn’t gotten ten steps down the hallway when two kids collided, sending a flurry of papers into the air. The kids emerged from behind it, rolling on the floor, punching at each other.

Mr. Taggart and Mr. Song, both in the history department, stepped in to try and break it up, but Mr. Song stumbled on a stray backpack and crashed into Mr. Taggart. Then they started brawling. Fisher and Alex made for the end of the hall as fast as they could.

They turned the corner and saw Amanda and Veronica walking together. Amanda spotted them.

“Hey,” she said, waving. When Veronica looked up and saw Fisher, she started to turn on her heel and head back the way she’d come.

“Just a minute,” Amanda said, grabbing her shoulder. Veronica shrugged her hand off.

“What?” she said icily.

“Don’t you think you’re getting a little worked up about nothing?” said Amanda. “Fisher was just trying to show you a good time. It’s not his fault a bunch of wild animals showed up, or that FP set them off.”

“Are you saying I’m overreacting?” Veronica said, narrowing her eyes.

“I’m saying,” Amanda went on, “that it was an accident, and now you’re treating Fisher like the supreme master of all evil.”

“Don’t tell me how to treat him,” Veronica said, anger bubbling up from some deep reservoir Fisher had never known existed. “Don’t tell me how to treat anyone.”

“I’m trying to help you!” Amanda said, half growling. “Why can’t you see that?”

“I see that you shouldn’t stick your nose in my business,” Veronica said, hissing. “Or is it just too big to fit anywhere else?”

Amanda lunged at Veronica. Veronica smacked off Amanda’s glasses, which went skittering down the hall. And before Fisher and Alex could react, the two were grappling viciously. Amanda was a trained wrestler and got the upper hand quickly, levering Veronica to the ground and twisting an arm behind her back. But Veronica’s free hand found her fallen backpack, and she pulled out a little perfume bottle. She pointed it over her shoulder and got Amanda right in the eyes.

Fisher and Alex rushed forward as the two stumbled apart. Fisher grabbed Veronica and Alex grabbed Amanda, who was blinking and shaking her head furiously, her eyes beginning to tear up.

“And you said I was overreacting!” Veronica shouted as she strained at Fisher’s grip.

“You deserve it, you lunatic!” Amanda screamed back. “Let me go!”

“Okay, okay,” Alex said. “Just calm down, all right?” He finally released her.

“I didn’t ask for your help,” Amanda said, spinning and glaring at him. “Don’t ever try and stop a fight of mine again,” she said, her pointer finger about a centimeter from Alex’s nose. “Unless you want to land right in the middle of it.” She stalked away, leaving an even more confused Alex in her wake.

“This isn’t your business, either,” Veronica said to Fisher, tearing her arm away from his. “Stay out of it. And stay away from me.” She retrieved her backpack and disappeared around the corner.

Fisher and Alex looked at each other. Down the hall that led to the cafeteria, someone had let off the sprinklers, and kids were running and screaming, their arms sheltering their heads. Down the hall that led to the gym, a dozen fights were in progress, and the air was full of the sound of muffled punches.

This wasn’t natural. It was insane, and it was deliberate.

Fisher and Alex spoke at the same time.

“Three.”