Matilda shrugged it off and crammed her bag under her cot. Then she reached up to unfasten the lock on the window near her bed.

“Do yourself a favor and don’t open that window. The portable toilets are right outside.”

Matilda turned and found a girl standing in the doorway of the cabin. She was as pretty as the others, but something in her face gave her a kind expression.

“Ugh,” Matilda said as she refastened the lock.

“I heard you got stuck in Tiffany’s cabin. I thought it would be nice to come by and make sure you were still alive,” the girl said, laughing.

“Next time you might want to check on her, not me,” Matilda said.

“Don’t let Tiffany bother you,” the girl said. “She’s been cheering since she was in diapers, or so she says. None of us really know each other that well, but somehow on the first day she became the boss. I’ve seen her type before. I think she likes it when you fight back.”

Matilda nodded. “Then she’s going to love my right hook.”

“I’m Kylie,” the girl said.

“I’m Matilda,” she replied, remembering to practice her smile. Kylie gave one back, then offered to help her unpack. While they worked, she filled Matilda in on the other girls on the team: McKenna spent most of her day texting and updating her many online profiles; Pammy and Lilly were called “the makeup twins” and hogged every available mirror; the striking Asian girl with purple eye shadow was named Jeannie; the two African-American girls were Toni and Shauna. Including Matilda, there were nine more new girls, but Kylie hadn’t had a chance to meet them yet. Matilda did the math. All in all, she had sixteen suspects, but she was relieved to be able to cut three from her list. Eliminating Jeannie, Toni, and Shauna would make things easier. No matter how much plastic surgery Gerdie might have gotten, she couldn’t change her race. Still, that left thirteen girls.

Suddenly, McKenna returned to the cabin. “Hey, what are you two talking about?”

“You,” Kylie said.

Matilda could almost smell McKenna’s insecurity. It quickly turned to anger. “New roommates are losers!” she said as her fingers typed furiously on her phone. “Watch your step or I’ll post something a lot worse next time.”

The girls watched McKenna storm out of the cabin.

“Well, I guess we’re not going to be friends with her,” Kylie said with a laugh. “Anyway, it’s dinnertime. They’re serving meatloaf surprise. The surprise is that ten percent of the people who eat it actually survive.”

“I’ll catch up with you,” Matilda said.

When Kylie was gone, Matilda fell onto her bunk and jotted down what she had learned about the rest of the squad into a notebook. Since the girls looked and dressed so much alike, she was going to have to work extra-hard to keep track of them.

She joined the other girls at dinner, studying each of their faces. She’d seen hundreds of photos of the old Gerdie, but none of these girls resembled her in the least. It was frustrating, but not nearly as much as their endless excited chatter about how they were going to “bring it” and “show those wannabes why Team Strikeforce is the best.” Matilda feared she would leap onto the table and strangle one of them if they didn’t shut up, so she excused herself to go back to her bunk and get some rest. Tiffany gave her a nasty smile as she stood up.

“Get your beauty sleep, loser,” she said. “You need all you can get.”

Exhausted, Matilda made a quick report to Agent Brand and fell sound asleep.

At five in the morning Matilda discovered exactly what Tiffany had meant about needing her sleep. She was shaken roughly and told to get into her practice uniform. She got dressed as quickly as possible and rushed out for what would be a twelve-hour ordeal.

Matilda did her best to keep up, but the practice was more grueling than her spy training, which often included barbed wire, an obstacle course, and robots shooting lasers at her. Learning the routines was simple enough, but Tiffany insisted on perfection. She wanted the squad to act like it was of one mind, with each clap, kick, and cheer performed at the exact same moment. Over the course of the day she cut two of the nine new cheerleaders they had chosen from Matilda’s tryouts. The next day three more were gone. Shauna told Kylie and Matilda that Tiffany had accepted more girls than the team needed for the sole purpose of weeding them out.

“You mean I’m still trying out?” Matilda asked.

Kylie nodded. “Tiffany has already let McKenna, Pammy, Shauna, Toni, Lilly, Jeannie, and me know that we made the final squad.”

“How many spots are left?” Matilda asked.

“One.”

Matilda looked to the other three girls. It was important that she got that last spot.

When the second day of practice was over, she staggered into her cabin with complaining muscles and a head clogged with dance moves. She didn’t even bother to eat, just climbed into her bunk and fell fast asleep. She planned to wake in the night and search the other girls’ belongings for any clues that might point her to Gerdie, but exhaustion overwhelmed her. She slept until five a.m., only to be awoken to repeat the previous day.

Kylie smiled at her when they met on the practice field.

“Tiffany is the devil,” Matilda groaned.

“Yes. Yes, she is,” Kylie said.

“Quiet! Today we’re going to learn a move called ‘Shoot the Rocket,’” Tiffany said.

The girls gasped. Even the girls who’d already made the squad seemed shocked.

“What’s the Rocket?” Matilda whispered to Kylie.

“It’s an aerial stunt—very dangerous,” she said. “Most high schools have banned it. Even pro cheerleaders get hurt doing it. It’s superadvanced.”

“Pyramid!” Tiffany barked, and Kylie and the other girls quickly assembled into a human pyramid, six bodies stacked on top of one another. Tiffany climbed to the top. She stood on McKenna and Pammy’s backs and looked down at Matilda and the other three girls.

“Now listen up, ’cause I’m only saying this once. The Rocket is usually done with the help of a spotter who hoists the girl onto his hands at chest-level. Then you jump upward, do a corkscrew twirl, and land on your feet at the top of a pyramid. I say ‘usually’ because we do it differently.” She grinned. “We cut out the spotter. Watch carefully.”

Tiffany bent her knees and then leaped backward into the air. She did a corkscrew turn and then landed squarely on McKenna’s and Pammy’s backs. The girls let out a painful groan. Matilda could hardly believe what she had seen. It was an incredible move—like something only a highly trained secret agent might be able to do. Could Tiffany be the Mathlete?

“I think I’m going to be sick,” one of the other new girls said. She and another of the new girls ran off the field and were never seen again. Matilda and one other girl were left for the last spot.

“Maddie, let’s see what you can do,” Tiffany said, climbing down off the pyramid to watch from the side.

“Just let me check my inhalers—I get a little asthmatic and—”

“No one cares about your stupid disease,” McKenna said. “Are you going to do this stunt or not? I have text messages to respond to!”

Matilda climbed the pyramid slowly. When she got to the top, she could hardly stand up straight. It was clear McKenna and Pammy were trying to knock her off. She dug her shoes into their backs and they yelped in pain. Matilda smiled sheepishly at them and bent her knees. Leaping backward as hard as she could, she tapped her stealth inhalers and blasted into the air with a whisper-quiet thrust. She did the corkscrew spin during the flip and landed cleanly, making extra sure to plant her feet on McKenna’s and Pammy’s heads.

There was silence. Tiffany looked stunned, and Matilda’s sole remaining competition dropped her head and walked out.

McKenna turned to look up at Matilda angrily. “This isn’t over,” she said, then rocked hard. The human pyramid began to sway and buckle. Then it collapsed. If Matilda fell from that height, she’d hurt herself badly, so she fired the inhaler once more and up she went, spiraling and forward-flipping gracefully until she landed right in front of Tiffany. The team leader eyed her closely.