It was only when they got to the door of the gym that Rover froze, just like he had outside the vet’s office.

“Come on, boy,” said Amy, giving his leash a little tug, but the dog stayed perfectly still, taking in the various experiment stations without so much as a blink. Once again, Amy thought she saw the curtain pull back and reveal the cold, silent side of Rover … and this time, she thought, he seemed a bit scared as well.

“What’s wrong, boy?” Katie asked, scratching Rover under his collar.

Rover licked his chops … and then slowly stepped into the gym.

They walked through the fourth-grade section of the fair, which was mostly volcanoes; the fifth-grade section, which featured a lot of petri dishes and electric potatoes; and on to the sixth-grade section at the back, which had a solid mixture of projects. Amy saw several live animal experiments, including some turtles in a terrarium, a pet rabbit in a cage, and more than one ant farm. She smiled at Max Levine and Carla Wing’s presentation on raising deadly plants for household use, complete with a miniature poison garden they’d grown.

“Oh, wow,” said Dad, nodding to a table across the room. “That’s pretty cool. Ames, do you know those kids?”

Amy winced when she saw that he’d motioned to Jake and Valerie’s presentation. He wasn’t wrong, either—theirs was titled The Rat-Powered House and had four rats in a terrarium running on separate exercise wheels, powering a small lamp. They also had an iPad setup that showed how many extra volts each rodent was creating. Jake and Valerie stood proudly in front of the display, answering questions and allowing people to stare at the animals. Everything about the project was perfect—simple science, live subjects, and an electronic display. Even the lamp was a good-looking antique.

“Mitch,” hissed Mom.

“What?” said Dad. He smiled at Amy. “It’s not as cool as yours, kiddo. Whatever yours is.”

They reached her table, which she was sharing with Anderson Klizbe and Brendan Fields, who were showing off the soil makeup of the average lawn with a cross section of grass. Amy had Dad lay down Rover’s kennel cushion and whistled for the dog to come over. But Rover stayed still.

Next to him, Katie pouted, looking a little worried. She trotted over to Amy and motioned for her to lean down.

“Rover doesn’t want to be here,” Katie whispered in Amy’s ear. “He doesn’t want to do the experiment anymore. He says we should go.”

“It’ll be fine,” Amy assured her.

“Rover wants to leave,” said Katie, “or things’ll get bad.”