The Screaming Pterodactyl was a modern, high-speed roller coaster, with seats that hung down below large polymer pterodactyls, giving one the impression that he was being carried by the beast through twists, turns, corkscrews, and loop-the-loops.

“It is open today, isn’t it?” asked Regular Valerie.

“Yes, yes, of course. We have a temporary queue line set up so you can ride the same ride we’ve had for the last seven years. But Astrid designed a whole new queue system. Now, as you walk though the line, you go on a fantastic hike through the primeval world, with twenty-two realistic animatronic dinosaurs. I’ve had the power turned on for you and the security guard at the door will let you in. You can check it out on your way to the ride. When you get through, the cast member at the ride entrance will let you go right to the front.”

“We don’t really want to see a bunch of old dinosaurs, do we?” asked Denise.

“Of course we do,” said Christopher.

“Dinosaurs are awesome!” shouted Austin, making both Valeries wince.

“We have to support Astrid,” said Toby.

“Don’t I always?” said Denise.

“You do,” said Astrid, with a laugh. “You’re just not quiet about it.”

When they finished eating, they walked to a large building draped with canvas tenting, next to the roller coaster. A security guard was standing by a slit in the canvas and pulled it aside, revealing a door, which he then opened. Inside, they followed the marked path through the entryway and found themselves standing in the middle of a desert scene.

“We start with the triassic?” asked Christopher.

“I would have liked to have gone through the whole prehistory of the earth,” said Astrid. “Since I couldn’t, I decided to stick with the three geological periods of the dinosaurs.”

They walked around a large rock to find themselves threatened by a group of four coelophysis, hissing and snapping their teeth-filled jaws. At the top of a hill, they could see a ferocious ticinosuchus, while closer by an elephant-sized moschops tugged at the shaggy fern.

“That’s the ugliest dinosaur I’ve ever seen,” said Denise.

“It’s technically not a dinosaur,” said Christopher. “It’s a therapsid.”

They rounded a corner, went through an arched doorway, and stood at the border between a grassy plain and a conifer forest. The painted mural on either wall made it seem as if both went on forever. Right in the middle was a massive brachiosaurus, reaching up to pluck pine needles from a tree. Nearby a pair of allosaurus harassed a stegosaurus, and beyond that a Quetzalcoatlus, the size of a jet fighter, soared overhead. Other, smaller dinosaurs hunted through the trees.

“Now these are what I call a dinosaurs!” said Austin, looking up at the Brachiosaurus. “They’re so realistic. It’s like we went back in a time machine. Say, why don’t you invent a time machine, Astrid?”

“That’s not really possible,” said Astrid.

“Well, sure it is.”

“Don’t get her started on time travel,” said Denise. “We’ll never get to ride the roller coaster.”

Astrid and her friends passed on through the Jurassic period and through another arched doorway to find themselves at the foot of a volcano, steam rolling down from the artificial lava. Running along the hillside were psittacosaurus, caudipteryx, and ornithomimus. Snapping and squawking below were several velociraptors. A large beipiaosaurus browsed through low-hanging trees.

“What’s with all these chickens?” asked Denise. “I thought this was a dinosaur exhibit.”

“These are all anatomically correct,” said Christopher. “Most cretaceous dinosaurs had feathers.”

“No wonder Maxxim Industries is in trouble,” said Denise. “You’re spending all its money building robot dinosaurs.”

“Who says Maxxim Industries is in trouble?” wondered Astrid. “Did your dad say that?”

“Yes. Not my dad that works for you. He thinks you’re the greatest thing ever. My other dad— he said it.”

“Maxxim Industries is just fine,” said Astrid.

Walking around a lava flow took the group to a triceratops nursery, where two of the huge three-horned creatures were caring for some tiny tykes just emerging from their shells. But looking over this tranquil scene from beyond the bushes was an enormous tyrannosaurus rex.

“That’s odd,” said Astrid.

“What?” asked Toby.

“The t-rex should be roaring and chomping and generally being scary. It’s the only dinosaur not working. I think I’ll take a look at it. Maybe it’s something minor.”

“Trust Astrid to turn riding a roller coaster into an electronics experiment,” said Denise.

“You guys go on ahead,” said Toby. “I’ll stay with Astrid and fix the dinosaur, and then we’ll follow you.”

“You sure you don’t mind?” asked Valerie.

“Go ahead,” assured Astrid. “I’m sure we won’t be more than a minute.”

While Christopher, Austin, Denise, and the two Valeries continued through the last arched doorway to the ride entrance, Astrid led Toby to the base of the monstrous creature. Pulling out her pocket toolkit, she unfastened four screws on the tyrannosaurus’s hip and opened a large panel.

“Uh-oh.”

“Is that what I think it is?” asked Toby, pointing to a cylindrical metallic object behind the panel.

“Do you think it’s a pressure cooker connected to digital clock?”

“No, I think it’s a bomb.”

“Well, either way, you’re right.”