Benjamin’s voice was next. “Perfectly. You’re in the hypodermic needle now. Dr. Kim is preparing the injection.”

“How did it feel?” Agent Brand asked.

“Kooky.”

“As good a description as any,” Brand said. Flinch wasn’t sure, but he thought he heard the man chuckle. “OK, Agent. Prepare for the injection.”

“I’m ready,” Flinch said, and then he was swept away in the liquid. The lights went out and he was suddenly floating, untethered, and unable to get his bearings.

“Flinch?” Dr. Kim’s voice filled his head.

“Yes, I’m fine. I can’t see anything, but I’m fine.”

Benjamin’s voice was next. “I’m going to remotely activate some of the more basic functions of your containment suit.”

Two lamps on either side of Flinch’s helmet lit up. What he saw was incredible. He was swirling around gigantic, yellowish blobs that kept slamming into one another. He reached out to touch one and was surprised to find they were spongy and sticky.

“What are these things?” he asked.

“Just a second while we pull up visuals,” Ms. Holiday said. “OK, there it is. Oh my. That’s amazing.”

“Flinch, what you’re seeing are fat cells,” Dr. Kim told him. “They’re harmless, but you’re going to have to use your boosters to move through them.”

“Is there a lot of fat in a brain?” Flinch asked.

“Um, Flinch, we couldn’t inject you into Heathcliff’s brain. His skull is too tough for that. We had to find someplace softer.”

He heard the troublemakers laugh.

“Where am I?”

“Um … well—”

“Where am I?” Flinch cried.

“You’re in Heathcliff’s butt!” Wyatt roared.

The Antagonist walked up the sidewalk to Thomas Knowlton Middle School and eyed the steel barricades on the doors and windows. This wasn’t what he’d expected. He reached into his pocket for his phone, dialed a number, and waited.

“Hi, honey bear!” Miss Information said when she answered. “I hope you’re feeling evil.”

“I’m feeling very evil, but there’s a problem. There’s no way into the school. It looks as if it’s on some kind of lockdown. I’m afraid they knew we were coming.”

“Does someone have the boo-boo face?”

“No.”

“Is my shmuggins feeling saddy-sad?”

“It’s just depressing. I wanted to take over the world today!”

“Shmookin, kissy bear, don’t be sad!” Miss Information said. “I’m working on fixing the problem right now. You’ll be inside sooner than you can say ‘I love my superawesome girlfriend.’”

“I love my superawesome girlfriend,” he said.

Miss Information laughed. “Oh, silly, be patient.”

“Well, what am I supposed to do?” he groaned.

“Just relax,” she said. “Listen, evil is afoot and I have to get back to it. I’ll see you soon, my little love monkey.”

He put the phone in his pocket and looked around at the surrounding neighborhood. It was a bright, clear day. The street was empty. The circumstances were ideal for taking over the world. He sat down on the steps outside the school and wondered how far away the closest convenience store might be. He could go for a soda—maybe a bag of chips. World-conquering gave him the munchies. But he was feeling lazy. What if his girlfriend opened the school and he wasn’t there to storm in and take over?

No, he would just plant himself where he was and wait.

A car drove by.

Two birds fought over a worm.

Somewhere, someone was using a leaf blower.

He lay on his back and took out his phone again.

She hadn’t called. Luckily, he had just downloaded sudoku. That would keep him busy.

Flinch was flying through the fat cells using the containment suit’s foot boosters. Occasionally, he flew right into one of the cells and bounced off it as if he were in a bouncy castle. Eventually, he came across a massive tube.

“What am I seeing, Doc?” he asked.

“That’s the femoral artery, and you need to be inside it. It’s going to pump you up to the lungs. We can’t take you through the heart, which is the most direct route, because at your size its chambers would crush you with a single beat.”

“How do I get in?” Flinch asked. “There isn’t exactly a welcome mat.”

“You’re going to need the laser,” Dr. Kim told him. “Cut a hole just big enough to crawl through and no bigger. Platelets will come and repair the damage, but if you make it too big they won’t be able to get the job done and you’ll cause internal bleeding.”

“Great. Now I’m a surgeon,” Flinch grumbled. He pressed the button on his glove that activated the laser, then aimed carefully and fired. He cut a small incision, as he had been instructed, just big enough for his body, then fired his rocket boosters and flew right into the hole.

The second he was inside the artery, his body was swept away in a massive current as if he had fallen into the rapids of a mighty river. He was moving fast and was completely out of control.

“Flinch, your heart rate is spiking,” Brand said. “What’s going on?”

“I’m freaking out!”

“Just relax, Flinch!” Dr. Kim said. “You’re in the bloodstream and traveling fast. You need to get ready because the lungs are coming up. When I say ‘fire,’ aim a harpoon at the artery wall.”

Flinch struggled to get control of his body. After a while, he did the only thing he could think of and swam with the current. He glanced around. His helmet beams illuminated the way, and he saw what looked like huge red beanbag chairs floating around him.

“What are the red things?” he asked.

“Those are red blood cells,” Benjamin said. “They’re carrying oxygen through the body. The arteries carry them, along with white blood cells and a substance called lymph, all through the circulatory system. They shouldn’t be much of a threat.”

One slammed into Flinch, nearly knocking the wind out of him. “Glad to hear it!”

“How is the suit?” Ms. Holiday asked.

“It feels fine, but it’s awful loud in here,” Flinch said, holding his hands to his ears. Something was thumping loudly and getting even louder by the second. “I can barely think.”

“That’s Heathcliff’s heartbeat,” Benjamin chirped. “I’ll remotely adjust the volume from here.”

At once, the thump was quieted.

“Gracias!” Flinch said.

“OK, Flinch, prepare your harpoon,” Dr. Kim said. “Now, fire!”

Flinch pushed a button on his arm. There was a loud POP! and a long tether shot out of his hand. He could feel a rope unraveling from his chest plate as it trailed the harpoon, and then the harpoon’s sharp tip punctured the spongy artery wall. Suddenly, he was jerked out of the stream, flailing.

“OK, that worked.”

“Luckily, the artery you’re in is taking blood to the brain and so you’ve been pulled closer to your target,” Benjamin said. “Look up.”

Flinch did as he was told and saw a huge tunnel. At its center was a massive red muscle, opening and closing. It was the source of the pounding. “Is that Heathcliff’s heart?”

“Yes, it is,” Dr. Kim said.

“Good to know he has one,” Flinch muttered.

“You’re close to the lungs, which means you have to get out of this artery. Use the laser to cut another opening and zip through it.”

Flinch did as he was told, and, once on the other side, he saw two massive pink objects that inflated like party balloons and then deflated just as rapidly. He didn’t have to ask what they were.

“Do I go inside the lungs?” Flinch asked.

“Not yet,” Dr. Kim said. “We need to adjust your suit’s environmental controls for their increased pressure. We don’t want you to pop.”