It was a hot summer afternoon.
Jack and Annie sat in their living room. Jack was reading a book about weather. Annie was looking out the window.
“Let’s go do something,” she said.
“Too hot,” said Jack.
“We could ride our bikes to the lake,” Annie said. “And go swimming.”
“No way,” said Jack.
“We could—”
“Shh, please,” said Jack. “I’m trying to read.”
Annie was quiet for a moment. Then she gasped.
“Oh, wow, lightning! I just saw a flash of lightning out there,” she said.
“You’re joking,” said Jack. “Nice try.”
“No joke! I saw it!” said Annie.
“There’s not a single cloud,” said Jack. “You need clouds to have lightning.”
“Then it must have been . . . magic!” said Annie. “Come on, let’s go!”
“No, thanks. Have fun,” said Jack.
“You’ll be sorry,” said Annie as she rushed outside.
Jack waited for Annie to come back in from the heat. He waited and waited. But she didn’t return.
Jack put down his book. “I’d better check,” he said to himself. He picked up his backpack and headed outside.
Oh, man, Jack thought as he headed up the sidewalk. It must be a hundred degrees in the sun.
By the time Jack reached the Frog Creek woods, he was sweaty and out of breath. He crossed the street and walked between the trees. Even in the shade, the air was muggy.
Jack tramped through the woods until he came to the tallest oak.
“Hey there,” said Annie. She was leaning against the trunk of the tree. Next to a dangling rope ladder.
“I told you it was no joke,” said Annie.
“Right. No joke,” Jack said with a grin.
Annie grabbed the ladder and started up.
Jack followed. As they climbed into the magic tree house, golden sunlight slanted across the floor. The warm wood had a deep, rich smell of summer. In a shadowy corner was a piece of parchment.
“A note from Morgan,” said Jack. He picked up the note and read aloud:
 
In Old Philadelphia,
A paper must be signed.
Help Doctor Ben
Make up his mind.
 
“Doctor Ben?” said Jack. “Is Ben his last name or first name?”
Annie shrugged. “I don’t know,” she said. “Keep reading.”
Jack kept reading:
 
To get his attention,
Say “We’re from the press.”
Then do what you can
To ease his distress.
 
Listen to his thoughts.
If his fears start to grow
And he loses all hope,
There’s a place he must go.
 
’Tis a land filled with things
You see every day.
But these everyday wonders
Will show him the way.
 
“Hmm,” said Annie. “So Morgan wants us to go to Old Philadelphia. We have to find someone named Doctor Ben. Then we need to help him make up his mind to sign some kind of paper. That sounds easy.”
“Yeah, definitely easier than going to a Roman army camp or an island about to have one of the worst hurricanes in American history,” said Jack.
“Philadelphia’s not that far from Frog Creek,” said Annie. “They’re both in Pennsylvania.”
“Yep, my class took a field trip there,” said Jack. “It’s not that far in miles. But ‘old’ could mean we’re going far back in time.”
“That’s okay. ‘Old Philadelphia’ sounds charming,” said Annie.
“Charming?” said Jack.
“Yeah, like lovely and pleasant,” said Annie.
“Okay!” said Jack. “So, where’s our research book?”
They looked around. The only book in the tree house was their Pennsylvania book—the book that always brought them back home.
“Hold on,” said Jack. “I have an idea.” He picked up the Pennsylvania book and checked the table of contents.
“Yes! There’s a chapter called ‘Old Philadelphia, 1787.’ ”
“Cool, let’s go to 1787!” said Annie. “This book can take us there and bring us back home.”
“Exactly,” said Jack. He turned to a page that showed a drawing of a cobblestone street with women in long dresses, and carts pulled by horses.
“See, it does look charming!” said Annie. “Let’s go!”
“Right,” said Jack. He pointed to the drawing. “I wish we could go there!”
The wind started to blow.
The tree house started to spin.
It spun faster and faster.
Then everything was still.
Absolutely still.