I was sure Harry had been right in front of us as we ran into the clearing, but now he was nowhere to be seen. As usual, we were playing after school in our favorite part of the woods.

“This is weird!” said Keith. “He was right there!” He ran his hand through his buzz-cut Afro, and I noticed his fashionable shirt had come untucked as he spun.

“I know,” Emma replied, “it’s as if he’s disappeared into thin air!” She tucked her clean thrift-store skirt behind her knees as she bent to look under a bush, careful not to snag her tidy blonde hair.

“Unlikely!” snorted Aaron, wiping his palms on his old jeans, leaving smears of dust. “Harry’s too, um, solid to sud- denly become invisible!”

“Aaron, that’s not kind!” said Emma, just as another voice exclaimed, “Hey!”

Harry’s voice!

“Harry?!” we all shouted at once.

“Ye-es?” replied the voice, teasingly.

“Where are you? We can’t see you!” I called.

There was no reply apart from a quiet snicker. I felt gooseflesh creep up my arms and the back of my neck, and I wished I had brought my hoodie to hug close. “Er, guys, this really is weird,” I said. “How are we hearing him and not seeing him?”

Emma used her stern voice, “Harry, you’re creeping Ashley out. Come out from wherever you’re hiding.”

“Oh, OK, you guys. Disculpa, Ash,” came the voice again. I smiled at his choice to use Spanish to apologize. My friends were so considerate of my Puerto Rican heritage, but I still didn’t have a clue where Harry could be. “Up here!” he said, and we looked up into the branches of the big old sycamore tree to see Harry’s freckled face grinning down at us between the early summer leaves.

“But how —?” began Keith as we all stared, open-mouthed.

“You’ll never guess what I found,” said Harry, pushing his glasses back up his nose. “It’s awesome! Look around the other side of the tree.”

We trooped around the tree and saw a long ladder reaching up into the branches.

But we know this place,” said Aaron, shoving his messy mop of hair from his pale forehead, “and that’s never been there before.”

“And it looks old,” Keith mused, “like it’s been there a long time.”

Keith was right. The ladder looked sturdy enough, but it was gnarled with age, and creepers had grown around some of the lower rungs.

“Come on up,” said Harry. “You’ll never believe what’s up here!”

Keith went first, followed by Emma and me, then Aaron. When we reached a platform at the top of the ladder, we found Harry standing in front of a small treehouse.

“Welcome, my friends,” he started in his best showman’s voice, “to a wonder you will never forget!”

“How the—,” “But—,” “We’d have—,” we all started saying at once.

“There’s more,” said Harry. “Come inside!”

“Huh?” said Aaron, flipping his hair out of his eyes. “I’m no scientist, but I can tell you that we won’t all fit in there!”

“He’s right, Harry,” I said softly. “Maybe we can go one at a time.”

“OK,” replied Harry, wiggling his eyebrows mysteriously, “but I think you’ll be surprised.” And with that, he disappeared into the treehouse.

Keith followed, and we heard him exclaim, “Wow! He’s right—you really need to see this, guys!”

We looked at each other hesitantly, then followed Keith through the doorway.

I had to touch the wall nearest me for balance as I tried to get my head around what I was seeing. The inside of the treehouse was huge! As big as our garage, at least! My neck prickled again, but I was more excited than spooked.

“This isn’t,” I started, “I mean, this is... like, magic, right?” “It’s gotta be,” breathed Keith.

“I can’t think of any rational explanation,” said Emma. “How did you find it, Harry?” asked Aaron, looking slightly dazed.

“Well, it was my turn to hide, remember?” started Harry.

“And I ran into the clearing. I thought I’d hide in the bushes, but there were ants and bugs all over them, so I ran behind the tree. I closed my eyes, just for a second, and I thought, ‘Please, please, don’t let them find me,’ and when I looked, the ladder was...just there in front of me. So I climbed up and found this place. Then you guys came, and you couldn’t see me or the ladder.” He giggled. “It was cool!”

We looked around the huge room. It was impossible that it could be this big, yet it was. It seemed to stretch way beyond the branches of the old sycamore tree. The floor and walls were made of long planks of wood. There were a few cobwebs in the corners, and it smelled like dust and stale air.

There were four windows, one on each side, all looking out onto thick leaves and branches. Pushing his head through one, Keith exclaimed, “There’s a kind of platform all the way around the edge! How is that even possible?”

The rest of us clustered around him to look out. Then Emma went to the doorway and disappeared outside. Two seconds later, she stood on the other side of the window.

“It’s, um, small again on the outside,” she murmured, sounding far less certain than she usually did.

“OK, this is cool!” Aaron declared. “This is seriously cool.” “What is this place?” I asked.

“I don’t know,” shrugged Keith, “but it doesn’t look like anyone’s been here in a long time.”

“So now it’s ours!” said Harry.

Emma came back in, and we all took a turn going outside onto the platform and walking around the treehouse. From the outside, it was the size of a small toolshed. Inside, it really was as big as a double garage. It made me feel dizzy stepping in and out, so I went in and sat in the middle of the floor.

Soon the others joined me. We were all delighted with our discovery and started discussing how we could make it feel more like our place. I thought we could maybe haul some beanbags up, and Emma suggested bringing cooler boxes for food and drinks.

We were all making suggestions at once, laughing and joking, slightly breathlessly, when Harry blurted out, “You know what I’d really like to do? I’d like to find out when thisplace was built. I wish I knew who built it!”

As Harry spoke, the floor of the treehouse began to vibrate. We looked at each other, wide-eyed. I felt a falling motion in my stomach, and I let out a little scream.

“Oh no!” gasped Keith, “It’s going to—”

But he didn’t get to finish what he was saying because just then something happened that would change our lives forever.