“They don’t eat French toast in France,” Pufferfish grumbled.

Flinch continued tearing at his bindings. Soon he heard a snap and his hands were free. Against his better judgment he turned to see what the sharp object was. It was a skull with a jaw full of broken teeth. He had put his hands into its mouth!!! Ugh!!! He danced around, trying to shake the creepy feeling.

“Now, for the harness,” he said when he got himself under control. He eyed it closely, searching for damage. As one of the most hyperactive kids in the world, Flinch was doomed to a life full of the jitters until he received his upgrades. Tiny robots called nanobytes turned the sugar that he consumed into raw power, then channeled it into the harness, which focused it and allowed him to dial it up or down at will. Without it, he was just a kid who ate too many cupcakes and rambled when he spoke. But how had the thugs known to disable it?

One of the harness’s power cords had been yanked out. Flinch reinserted it, and the chest plate glowed to life with a familiar blue light. Immediately, he felt the energy coursing through him.

“Problemo numero dos has been solved. How much time do I have?”

“Nine minutes,” Pufferfish said.

“I need someone to guide me through these tunnels. Can we scan them for the bombs?”

“Already done,” Pufferfish said. “Each bomb is producing a low-grade electronic signal, which I can detect because there is very little power down there. But they’re spread out, and worse, these tunnels are hundreds of years old and some have collapsed, so be careful. The first one is only a few yards ahead of you.”

Flinch blasted forward, fueled by the harness. He left a trail of dust and bone behind him.

“Make a left at the fork ahead,” Pufferfish said. “Radiation signatures tell me the explosive device is just beyond.”

Flinch did as he was told, tearing through the tunnels. He rounded a bend in the path, noticing stones inscribed with strange dates and numbers. One read OSSEMENTS DU CIMETIÈRE DES INNOCENTS DÉPOSÉS EN AVRIL 1786.

“What’s with the markers down here?” he asked.

Pufferfish cleared her throat. “They’re sort of on-site lists of when people were taken from the original cemetery and brought to the catacombs. They’re not important to the mission.”

“I’m trying to keep my mind off all the dead people,” Flinch said.

“The bombs aren’t enough distraction?” Wheezer asked.

“There!” Pufferfish cried.

Flinch came to a screeching stop. The first explosive was crammed into a dark corner of the tunnel. It was about the size of a small paperback book, with a timer on the front and several glowing lights. “Got the first one!”

“Describe what you see,” Pufferfish said.

“It’s small and metal and there’s a clasp on the side. Hold on, I’ll open it. OK, there are two long tubes filled with liquids. One looks like cream filling and the other like fruit punch. At the ends of the tubes are needles, like in a doctor’s office, and they are inserted into two small bricks of white clay that look like saltwater taffy. And it’s all hooked up to a black box—the timer.”

“Plastic explosives,” Wheezer said.

“Only worse,” Gluestick said.

“Huh? Why is it worse?” Flinch asked.

“Don’t panic,” Gluestick said.

“Don’t tell me not to panic! Now I’m panicking!”

“It’s a hybrid bomb. The plastic explosive is probably enough to knock the ceiling down, but the explosion isn’t enough for the whole tunnel, so Kapow added a chemical element. I can’t know for sure what is in the tubes without doing tests, but I suspect it’s a form of acid. The bomb knocks out the tunnel and the chemicals eat the limestone from below. It spreads and disintegrates everything it touches until there’s a gigantic hole that can’t be filled in or built upon. Not only is this lunatic trying to cave Paris in on itself, he’s making sure no one can fix the damage.”

“And how do I stop it?”

“Just a second. I’m accessing the information now,” Pufferfish said. “OK … remove the cover of the black box, and inside there should be some wires.”

Flinch reached down and delicately removed the cover, but he didn’t see just a few wires, as he had expected. Instead, he saw dozens … scores … hundreds. The guts of the timer looked like multicolored spaghetti spilling out all over the place.

“Find the green wire,” Pufferfish said.

The green wire? There were a hundred green wires! The more he dug, the more he found. There was no way he was going to be able to do such delicate work.

“OK, Plan B!” Flinch said, shoving the bomb into his pocket. “Where’s the next one?”

“Flinch—”

“Andale!” Flinch cried. “We don’t have time!”

“Fine! Keep moving down the tunnel, then make a left at the curve ahead and go up to the next level. Wow! Some of these tunnels run parallel to one another. It’s like an ant farm down there. Anyway, the next explosive is in an alcove,” Pufferfish said.

“This is going to take forever! What if I just knock down the wall?”

“Well, I—” Flinch slugged the wall and the limestone collapsed, opening a passage to another tunnel. There he found the second bomb. Finally, one of his decisions had worked. “We’re on a roll now. Where’s the next one?”

Pufferfish led the boy through the catacombs. One by one he smashed through the ancient limestone walls and found Kapow’s bombs. He tucked each new device into his pants and hoped that he wouldn’t accidentally set off the chemicals inside.

“How many left?” Flinch asked.

“One,” Pufferfish said. “It’s in a section of the tunnels called the Port Mahon Quarry.”

Following her instructions, Flinch smashed his way to the last of the explosives. What was it the teachers said in math class? “The shortest distance from point A to point B is a straight line”? They were right. It was even shorter when you had a superpunch.

Finally, he found himself standing before an iron gate with a concrete wall on the other side.

“OK, I’m here,” Flinch said. “Looks like they don’t want anyone to go past this point.”

“Records show the city closed up this tunnel because the ceiling was collapsing. A few workers died here about a decade ago.”

“How did he get a bomb back there?” Flinch asked.

“There are other ways into the quarry,” Pufferfish explained. “This is the most direct. How are you doing?”

Flinch looked down at the light on his harness. Knocking down walls and running at over seventy miles an hour had used up a lot of fuel. He turned the knob on his harness to the highest level and then pulled with all his strength at the iron gate. It came away in his hands. Now he just had to punch through the concrete.

He gave it two wallops. There was a huge orchestra of rumbling, a thick cloud of dust, and a blast of cold air. When the dust settled, he could see the last bomb waiting on the other side. He scooped it up and shoved it into his pocket with the others, then turned to make a dash for the exit. But he wasn’t feeling all that fast. The powerful punches had sapped almost all of his strength.

“I hope there’s an exit nearby because I’m on empty,” Flinch said.

“It’s just off to the left,” Pufferfish told him.

Suddenly, everything went black.

“What happened to my contacts?!” Flinch cried. He blinked furiously but nothing happened. He still couldn’t see anything.

“The battery must have died,” Gluestick explained. “They last only a few minutes. Don’t you remember the—”

“Yes, I KNOW! The briefing!” Flinch growled. “I’m in the dark. I’m out of power. I’ve got ten bombs shoved in my pants, and I’m surrounded by skeletons. This is the worst mission ever!”

Desperate, he reached out for the wall and felt the cold, ancient bones on his fingertips. Fighting the urge to gag, he started walking as quickly as possible, stumbling occasionally on something—what, he dared not imagine. But after a while he saw a shaft of light shining down on a spiral staircase. With what was left of his power, he raced up the steps and darted out onto the streets of Paris. Gluestick and Braceface were waiting for him at the exit.