"Don't threaten me," the principal growled. "My boy isn't going to ruin our plans."

"Then we understand each other," the voice said. "Tonight we'll push forward, if you can find the time."

Hamelin's voice was so angry it was shaking. "Don't question my dedication. This was my idea after all."

"I'm glad to see you still remember that."

Hamelin spun around and rushed back up the tunnel, narrowly missing stepping on his own son, who just managed to leap out of the way.

"Are you OK?" Daphne asked, taking Wendell's hand in her own.

"I can't believe it," the boy said.

"We should go farther into the tunnel," Sabrina suggested. "We need to know where they are digging to." Everyone agreed, but just then something crawled out from around a corner and stopped the group in their tracks. An enormous brown mouse as big as a semi truck lumbered toward them. The rodent's pink nose and whiskers flicked and twitched as it sniffed at the children. Sabrina knew that at their current size they'd make a great snack for the hungry mouse.

"Eat the cakes," Sabrina advised, eyeing the mouse.

The children unwrapped their cakes and were just about to eat them when the mouse barreled forward and knocked Sabrina down. Daphne screamed and Puck leaped forward and dragged Sabrina to her feet. Unfortunately, she had dropped her cake right in front of the beast. The mouse spotted it, sniffed it, and with a quick flick of its tongue, ate it.

"That was a bad thing, wasn't it?" Sabrina said, sheepishly.

"Oh, man," Puck said, quickly shoving his own little chocolate cake into his mouth. "This is going to be awesome."

Daphne and Wendell were already munching their cakes, too, when Puck offered Sabrina his pinky.

"Hang on Sabrina," Puck said, flashing his devilish grin. "This is about to get interesting."

Sabrina grabbed his pinky finger and held it tightly just as the first changes affected the mouse's body. It sounded as if someone were blowing up a balloon. A ripple rolled across the mouse's skin and its eyes widened as its body inflated by a thousand times, yet its little legs and head stayed the exact same size, causing its massive body to plop to the ground. This was followed by a loud, squeaky rubber sound as the rodent's feet, legs, and head expanded in size. The children dashed down the tunnel to avoid the quickly expanding mouse.

Puck, meanwhile, was growing in the same awkward manner. His legs got big first, pushing him to his normal height and sending Sabrina soaring high into the air. When his upper body and hands finally followed, his pinky got thicker. Sabrina held on with all her might. Luckily, Puck was paying attention. He quickly swung her into his shirt pocket, where she clung to the top, just as Puck's head inflated.

Meanwhile, Daphne's head and feet were the first to inflate and the not-so-little girl hobbled around like a pumpkin that had suddenly sprouted shoes and was making an escape from the patch.

"I don't like this at all," she groaned. No sooner had she complained than her legs sprouted up like over-eager cornstalks, followed by her upper body, and lastly her neck. Wendell experienced the same kind of disturbing growth.

"It's all good," the runny-nosed detective announced, checking for all ten fingers. But what he didn't see was that it wasn't "all good." The mouse was also getting bigger and bigger until it was nearly as wide as the tunnel, and worse, it seemed very, very angry.

Puck grabbed Daphne and Daphne grabbed Wendell and they all rushed down the tunnel and up the stairs. When they got to the top, Daphne and Wendell raced across the room to the door, unlocked it, and hurried into the hall. Puck followed close behind, giggling like an idiot.

"Do you laugh every time we're in trouble?" Sabrina shouted.

The boy looked down into his pocket. "What are you squeaking about?"

When he was safely in the hall, Puck slammed the door shut and the children leaned against the walls on either side to catch their breath.

"I don't think we have to worry about him anymore," Puck said.

Just then, the door flew off its hinges, slammed against the opposite wall, and fell heavily to the floor. The giant mouse lumbered into the hallway and roared angrily. It was as big as a stuffed buffalo Sabrina had seen at the Natural History Museum. It let out a deafening squeak and licked its gigantic front teeth. To make matters worse, the dismissal bell rang and every classroom door opened. The hallway was immediately flooded with a sea of noisy children, eager to get to their next class. The mouse stomped hard, creating a chasm in the shiny floor, and all conversation ended abruptly.

"Well, piglet, you wanted to do the dangerous stuff," Puck laughed, as he turned to a stunned Wendell. "Be my guest!"

OK, everyone, there's no need to panic. We're professionals and we know how to handle things like this," Daphne assured the crowd of stunned students. She flashed her shiny badge to the crowd. A teacher fainted to the ground as the mouse let out an ear-shattering squeal and stomped its giant paws on the floor.

"Stay calm," the little girl said. "It's as afraid of you as you are of it."

All at once, every kid at Ferryport Landing Elementary freaked out. They screamed and ran toward every available exit. Some raced into classrooms, barricaded the doors with desks, and climbed out windows.

Puck peered into his pocket and smiled at Sabrina.

"Hang on, I've got a plan," he said, flashing her a grin. He spun around on his heels and transformed into an orange and white alley cat. Sabrina found herself clinging to the cat's ear as it charged toward the giant mouse. Once he got up close, Puck the cat hissed aggressively, but the mouse only stared down at him. Suddenly, what Sabrina could only describe as a smile crept across the mouse's face. It leaned its head down to the cat, opened its mouth, and roared angrily. Puck's short tabby hair was blown back as if he were standing in a heavy wind and Sabrina nearly Hew off his ear. The cat backed away and transformed into a boy again.

"It was worth a try," Daphne shouted.

"Don't worry," Puck said, with Sabrina back inside his shirt pocket. "I've got a million more ideas where that one came from." The boy spun around to face the mouse and his wings popped out of his back. Flapping strongly, he soared over the mouse, spun around, and landed on its back.

"Yee-haw!" he cried, jabbing the heels of his feet into the mouse's side. The mouse squealed in pain, lifted itself on two legs, and kicked wildly, causing Puck to bounce around like a rodeo cowboy and Sabrina to be tossed around mercilessly inside the boy's pocket.

The giant mouse slammed into walls, broke down doors, and put serious dents into a row of lockers. It shattered a trophy case, sending glass, brass track medals, and bowling prizes skittering down the hallway. It crashed into a banner announcing the library's bake sale and ripped it off the wall.

Of course, Puck laughed at every effort the mouse made to buck him off. Sabrina suspected he'd ride the beast all day if it didn't get tired first.

"Puck, cut it out!" she shouted, clutching the top of the pocket, but she knew the boy couldn't hear her over the commotion he was making.

Daphne rushed across the hallway, avoiding the mouse's wicked flapping tail. She reached into her pocket and pulled out her half-full Drink Me juice box and aimed it at the mouse's mouth.

"Daphne, you're a genius!" Sabrina cried.

Daphne reached back like a big-league pitcher, waited for the mouse to open its gaping mouth, and tossed the juice box as hard as she could. Unfortunately, instead of slipping down the mouse's throat, the box bounced off one of the rodent's gnarly yellow teeth and fell to the ground. The mouse stomped down on the box, spraying the contents all over the hallway.