“That’s possible?”

“You read the articles, didn’t you?”

I bite my lip. “Yes. I’m the one who found them.”

“So then you should get what I’m saying.”

This is starting to remind me of a reading comprehension test. Whenever I get a bad grade, I always try to explain to Mom that I did read the book. And just because I can’t remember what color shirt the character was wearing on page six doesn’t mean that I didn’t read it. I mean, I was too busy crying about the dead dog at the end to remember what the characters were wearing.

“You do, don’t you?” Cora presses.

I nod my head yes even though I really don’t get it, and I’m grateful that I’m still in front of Cora so she can’t see my face. To me, a time machine equals time travel. We need a time machine. That seems like the most basic of basic things.

“We don’t need a time machine if we can find a wormhole, right?” Cora says.

“Right,” I parrot. “But how do we find a wormhole without a time machine?”

“That’s the challenge!” Cora’s voice is more animated than it’s been all day. Challenge is a word that I’ve never been excited about. Challenges are puzzles and I’d almost forgotten how much Cora loves puzzles. Memories of sleepovers spent watching Cora put together a zillion pieces while I half-heartedly matched a few border pieces race through my head.

We reach the edge of the creek. I spot the giant oak tree on the other side. My heart cartwheels in my chest. This is my chance to show her that I’m not completely worthless. The giant oak tree is the zillion-piece puzzle that I’ve put together.

“Okay,” I say, pointing at the creek. It rained some last night, but the water still isn’t very high. “We’re gonna have to cross.”

Cora’s caught up with me by now. She’s standing by my shoulder. She eyes the water and frowns. “I’m not sure about that.”

“Come on, Core. It’s not that big of a deal.”

“Uh, I don’t want to slip and fall.”

“You won’t. Here, watch me.” I leap out onto the first rock and turn back to Cora. I stretch my hand out. “Come on. I won’t let you slip.”

Cora hesitates, but then she grabs my hand. We slowly cross to the other side of the bank this way, me hopping to the next rock, Cora reaching to grab on to me. She drops my hand once we’re standing in front of the giant oak tree.

“This is it,” I say, my voice small and quiet like its three inches tall, a mushroom of a voice.

She cranes her head back to look all the way up at the tree. “This is what you wanted to show me?”

“I think—” I start, and then correct myself. “I feel like there’s a wormhole here. I call it the giant oak tree.”

“The giant oak tree,” Cora repeats.