DR. Z'S ADVENTURE PARK

The Carvers stood first in line for the grand opening of the Dragon Tooth, advertised as the greatest thrill ride in amusement park history. Samantha gazed back at the zigzag of customers, people of every shape, size, and color. She couldn't believe her good luck.

The word "excited" didn't exactly describe Sam's feelings. She was ecstatic, overjoyed, tweaked, gonzo, completely over the moon. Her hands fluttered like hummingbirds, darting up to her thick black hair, drifting skyward, then diving down into her pockets.

Who could blame her? Sam was visiting her favorite place on the planet: Doctor Z's Adventure Park. No one loved amusement parks more than eleven-year-old Sam Carver. She loved everything about them. The crowds, the food, the noise — music blaring, bells dinging, children screaming,

"I SCREAM, YOU SCREAM, WE ALL SCREAM ON ROLLER COASTERS!"

Sammy loved the buttery smell of popcorn that filled her nostrils, the sweetness of cotton candy, the grease of hot dogs and burgers. But most of all, she loved the rides, every single one — the Whirligig and the Wheel of Wonder, the Windseeker and Skyscreamer, the Gravitron and Richochet and Cloud Chaser. She worshipped the Wall of Death and dearly loved the Spiral of Doom.

For Sam, there was only one rule: the scarier, the better. And after each ride, Sam would cry: "Again, again, again!"

She checked — once again, for the 100th time — for the thick, cardboard ticket in the front pocket of her dress. She bounced on her heels in anticipation. Her eyes lifted to watch a red-tailed hawk glide through the clouds. Bird in the sky, she thought, I know how you feel.

"I'm sooooo excited!" Sam told her parents. "I feel like a bottle of soda, all fizzy inside, ready to pop."

"Try not to explode," her father said. "That might be messy."

Mrs. Carver looked up from her folded newspaper. She enjoyed word games, and completed the crossword puzzle every morning. Sam liked to help her mother solve the Daily Jumble and play with anagrams, where you rearranged the letters of one word to form new words.

She pretended her own name, Samantha, was an anagram.

A HATS MAN ASH MAN AT HAM ANT AS

Oh well, it was a disappointing list.

Sam was certain that today was going to be the best day of her life. She turned to her parents and beamed a smile of pure sunshine. "Thanks for bringing me, Mom and Dad. I can't believe how happy I am."

Months before, Sam had entered a contest by clicking on a link and, amazingly, despite the odds, actually won a prize. Her reward? A ticket to be among the first customers to enjoy the Greatest Thrill Ride Ever Created. But was Sam brave enough?

Oh yes, surely she was. Nothing frightened Sam Carver. Nothing, that is, except for dentists, bats, and homework. The usual things. Dentists, of course, with their fat fingers fumbling in your mouth. But bats creeped Sam out the most, with their leathery wings and tiny teeth and weird human faces.

Besides, homework scared everybody!

THE THIN MAN IN A DULL BLACK SUIT

Behind the entrance gate, a man sat upon a high stool, legs crossed, fingers knotted on his lap. He appeared to Sam like a grim vulture, a strange and hostile bird of prey.

Sam could see that he was unusually tall, with long arms and legs jutting out in awkward angles. A lanky man dressed in a faded black suit, plain white shirt, and narrow tie. His shoes were scuffed and battered. The man had a sharp nose, a down-turned mouth, and restless eyes that never stopped moving.

The man guarded a door that led into a huge, warehouse-size building. Ginormous, Sam thought. On the wall was the painted head of a massive dragon, yellow eyes gleaming with menace, teeth sharp as knives. In exotic letters that almost looked Chinese, a sign read,

THE DRAGON TOOTH

According to articles that Sam had read on the Internet, this particular ride had been in development for more than five years, and was considered the crown jewel of Dr. Z's empire. Details were top secret. No one knew whether it would be a new kind of roller coaster or ... or ... it could be anything! Part of the fun for Sam had been imagining what the ride might possibly be.

"Maybe they drop you from, like, a million feet in the air," Sam speculated.

"Sounds high." Her father whistled.

"Or maybe it's like one of those slingshot things, like something with bungee cords, or with crazy g-forces, or —"

Sam could see that her father was bored. While Mrs. Carver patiently filled in the boxes of her crossword puzzle, Sam's father sweated in the summer heat, and squeezed the back of his neck. He checked the time on his cell and frowned. "We've been waiting almost two hours," he groaned. "Ever since my time in the army, I promised myself I'd never stand in line again."

Sam shot her father a look. "It's okay, Dad. The ride will be totally worth it."

"I don't know, kiddo," her father replied wearily. "I feel pretty silly standing around like this."

The thin man cleared his throat with a growl. "Patience," he murmured.

He glanced at the sky. A flicker of worry flashed in his eyes. A change in light caused Sam's eyes, too, to lift skyward. As if the air had shifted somehow, as if the sky changed color. It happened fast, in a blink, but it felt impossibly ... WRONG. Even worse, Sam felt as if she was being observed by someone, or something. A camera in the sky, a watchful eye. Sam scolded herself for being a goofball, and decided to think happier thoughts.

Sam looked around. No one else seemed to notice anything, except for the man in the dark suit. His gaze kept returning to the sky, lips pursed thoughtfully. He had the nervous habit of rubbing a thumb against the crook of his forefinger.

"Excuse me, sir? Will you be letting us in soon?" Sam asked.

The man made no reply.

Sam pressed forward. "Do you know what the ride is like? Have you seen it?"

He now directed his cold gaze at Sam. "I have," he said. "You will not be disappointed."

"Have you met Dr. Z?" she persisted.

The man smiled, but without warmth. "Ah, the mysterious Dr. Z. What do you know about the owner of this amusement park?"

"Lots," Sam said. "He's one of the most mysterious men in the world. His real name is Phineas Z. Overstreet. And he's a reclusive, eccentric billionaire!"

"Eccentric," the man replied. "A big word for 'crazy.'"

Sam laughed. "He's brilliant, and lives in his own world. He won't let anyone take his picture. And he's crazy about games, just like me." She knew that Mr. Overstreet made his fortune as an inventor. Then the sky did it again. As if the clouds had rearranged, or somehow the planet tilted in a new direction. All in the sliver of an instant. But Sam noticed. She glanced...