1Jack crawled through a hole in the tree house floor.

2Wow. The tree house was filled with books. Books everywhere. Very old books with dusty covers. New books with shiny, bright covers.

3“Look. You can see far, far away,” said Annie. She was peering out the tree house window.

4Jack looked out the window with her. Down below were the tops of the other trees. In the distance he saw the Frog Creek library. The elementary school. The park.

5Annie pointed in the other direction.

6“There’s our house,” she said.

7Sure enough. There was their white wooden house with the green porch. Next door was their neighbor’s black dog, Henry. He looked very tiny.

8“Hi, Henry!” shouted Annie.

9“Shush!” said Jack. “We’re not supposed to be up here.” He glanced around the tree house again.

10“I wonder who owns all these books,” he said. He noticed bookmarks were sticking out of many of them.

11“I like this one,” said Annie. She held up a book with a castle on the cover.

12“Here’s a book about Pennsylvania,” said Jack. He turned to the page with the bookmark.

13“Hey, there’s a picture of Frog Creek in here,” said Jack. “It’s a picture of these woods!”

14“Oh, here’s a book for you,” said Annie. She held up a book about dinosaurs. A blue silk bookmark was sticking out of it.

15“Let me see it.” Jack set down his backpack and grabbed the book from her.

16“You look at that one, and I’ll look at the one about castles,” said Annie.

17“No, we better not,” said Jack. “We don’t know who these books belong to.” But even as he said this, Jack opened the dinosaur book to where the bookmark was. He couldn’t help himself.

18He turned to a picture of an ancient flying reptile. A Pteranodon.

19He touched the huge bat-like wings.

20“Wow,” whispered Jack. “I wish I could see a Pteranodon for real.” Jack studied the picture of the odd-looking creature soaring through the sky.

21“Ahhh!” screamed Annie.

22“What?” said Jack.

23“A monster!” Annie cried. She pointed to the tree house window.

24“Stop pretending, Annie,” said Jack.

25“No, really!” said Annie.

26Jack looked out the window.

27A giant creature was gliding above the treetops! He had a long, weird crest on the back of his head. A skinny beak. And huge bat-like wings!

28It was a real live Pteranodon!

29The creature curved through the sky. He was coming straight toward the tree house. He looked like a glider plane!

30The wind began to blow.

31The leaves trembled.

32Suddenly the creature soared up. High into the sky. Jack nearly fell out the window trying to see it.

33The wind picked up. It was whistling now.

34The tree house started to spin.

35“What’s happening?” cried Jack.

36“Get down!” shouted Annie.

37She pulled him back from the window.

38The tree house was spinning. Faster and faster.

39Jack squeezed his eyes shut. He held on to Annie.

40Then everything was still.

41Absolutely still.

42Jack opened his eyes. Sunlight slanted through the window.

43There was Annie. The books. His backpack.

44The tree house was still high up in an oak tree.

45But it wasn’t the same oak tree.