Zach was so lost in thought that he didn’t realize Nathan was speaking to him. “And what about you, Mr. Squad Tactician? You’re supposed to be the gaming expert around here. What do you think we should do?”

Blinking fast and making snorting sounds, Zach reached for his backpack and skateboard. Emma was sure he was going to bolt. Should she speak up and defend him? Before she had time to decide, Zach stood…and faced Nathan. He was stock-still. Suddenly not a twitch or a snort. Nathan blinked with surprise as if that was the last thing he expected. Then, in a measured voice, Zach said, “I think we should let them hack us all they want.”

Again, there was quiet in the computer lab. Emma was struck, not just by what Zach had said but by the way he’d said it. Self-assured and without any of the usual jitters or goofiness.

“That’s the stupidest thing I ever heard,” Nathan argued. “What’s the point?”

But Emma saw the point. It wasn’t stupid. It was smart and insightful. “He’s right,” she said. “What’s the point of having a club if all you’re going to do is cheat?”

Nathan’s face grew pinched. Emma could tell that he knew Zach was right. Not that Nathan would ever admit it. Instead, he spun around and headed out the door without saying goodbye.

Now Zach and Emma were alone in the computer lab. Outside, the sun was shining, and Emma decided she wouldn’t mind walking home after all. When she stood up, Zach gave her a curious look. It struck Emma that in all the weeks they’d been together on the Allied squad, they’d never had a chance to talk one-on-one.

“Feel like walking?” she asked.

Zach started to do his rapid-blinking thing, then caught himself. “Uh, okay, sure.”

They left the lab. School might have been over, but the building wasn’t empty. Out of nowhere four DIY model cars came racing toward them. Emma and Zach jumped out of the way as the little cars zipped past, their electric motors whining. The cars turned at a small orange traffic cone down the hall. One took the turn too quickly and rolled over, but the other three raced back past Emma and Zach before skidding around a corner and disappearing.

“Radio controlled,” Zach said. “With minicams.”

Keeping an eye out for more small high-speed vehicles, they walked toward the school lobby. Once again Zach began clearing his throat and sucking air noisily through his teeth. Hoping to help him relax, Emma said, “That was really smart, telling Nathan we shouldn’t do anything about the malware attack.”

Zach didn’t reply. Suddenly he stopped. He was staring off, lost in thought. “I have to go back,” he said, and jogged away up the hall.

When Caleb got to the yearbook office, Ms. Dean and Callie Potendo were huddled together in front of a computer screen, looking at the student portraits the photographer had sent. Callie was one of the yearbook’s staff writers, but Ms. Dean must have corralled her for the job of reviewing the portraits.