I woke up the next morning with a pounding headache. It took me a couple of minutes to remember what had happened the night before. But slowly, it came back to me: running through the woods, the creek, Tom, Robin…

Ugh! I could never remember my head hurting this bad before. I walked slowly down to the kitchen and took some Tylenol, then practically fell into my kitchen chair. "Morning," I mumbled to Cassie.

"Morning," she said back with a mouth full of Cheerios. My sister definitely wasn't a morning person. She looked terrible: pale, dark circles under her eyes, and potential bad breath. I knew it was better to not say anything to her until she had fully woken up. Trust me, it's a lot safer that way.

As I ate breakfast, I thought about what had happened last night. I was really excited to hang out with Tom today and meet some new people. He seemed like a nice guy, and it would be great to know some people around here when school started – it would make me feel like less of a new kid. But something was so unsettling about Cassie's friend just disappearing like that…

We had ended up looking for Robin for over an hour, even though we were supposed to be home long before that. Since we were near the creek and hadn't even been talking for that long, Cassie and I figured that she couldn't have been far. At the least, we should have been able to see her footprints in the muddy path.

But we found nothing.

We called her name over and over and scanned the woods, but it was impossible to see anything as the sun set. Plus, even though I would never admit this to Cassie, I was still creeped out by the woods, especially after getting lost.

I pushed this out of my head. Today was going to be fun!

Cassie had finished her breakfast, so I figured it would be okay to talk to her now. "So, want to hang out with some people in the woods today? Tom invited me out there. Maybe you could call Robin and see if she wants to come too."

"Can't. Robin doesn't have a phone – she told me that her parents had it disconnected for a while."

Pretty weird. Who doesn't have a phone these days? But I really couldn't say anything – after all, our parents packed us up at the beginning of summer and moved us into the forest. That was pretty weird as well.

"Well, do you want to come anyway? It should be fun."

Cassie shrugged. "Sure. It's not like I have anything else going on around here. Maybe Robin will show up. She hangs out a lot in the woods already, she told me."

Cassie and I spent the morning raking our yard. I had seriously never seen more leaves in my entire life. Mom supervised us through the window and shouted out orders but never picked up a rake to help. By the time we were done, we had six giant bags of leaves.

"Now can we go out?" I pleaded. Mom finally agreed, and Cassie and I were off. "But I'm not racing. Walk with me, okay?"

"You're such a dork," Cassie mumbled, and promptly stuffed a wad of leaves down my shirt. We took off towards the self-made trail and made our way towards the center. "Where are you supposed to meet this guy?" she asked.

"Uh…towards the middle, I Guess. Wherever I was yesterday."

She rolled her eyes. "That helps a lot."

We started walking the way that I thought I had gone yesterday. So far, everything looked pretty much the same. But really, it's hard to tell in the woods unless you mark some sort of path. Really, we should have thought about doing that, but we didn't care at the time. All we were both interested in at the moment was finding kids to hang out with besides ourselves.

As we kept walking, I heard steps approaching. "Hey!" a voice called out. I recognized Tom, squinting in the sunlight. "Come on, let me show you where everyone is."

I introduced Cassie to Tom, and we started walking. As we pushed through the dense trees, Tom began to clear a path that I wouldn't have noticed otherwise. "Cool hiding place," I said.

"You have no idea," Tom laughed. He pushed aside a final tree and led us over to a group of kids. "Hey guys, this is Tom and that's his sister Cassie."

They all said hi, and each seemed friendly enough. Jason was short and stocky and fidgeted a lot with his Marlins baseball cap. On the other hand, Chris was super tall and looked like he could be in high school. Jill was short and freckled and looked like she was Cassie's age, and I could tell already that they were going to hit it off. Finally, there was Natalie, who was a really cute girl with curly blonde hair and green eyes. I hoped that she and I would have some classes together when school started.

"You aren't going to believe what we've been doing," she exclaimed. "It's kind of dorky, but…"

"What?" I asked, thinking it couldn't be any lamer than anything that Cassie and I had done all summer.

"Well, we've kind of been…playing tag."

"Tag!"

"I know, it's stupid, but so much fun."

I was about to confess that my sister and I had been doing the same thing all summer, but I quickly shut my mouth. Here was a chance for me to not be the dorky kid. I could be anyone I wanted in a new town. So instead, I said, "Tag, huh. Haven't played that in years."

"Yes you - " Cassie started, then shut her mouth after she saw the look that I gave her.

Jason started explaining the rules, which were pretty basic. The only difference was that the game took place all over the woods – there were no boundaries. However, there were multiple "safe zones" that we could go into at any given time. Jason pointed them out: the rock shaped like a horse, the tree with the robin's nest, the fallen log, and so on. However, we could only stay in each safe zone for two minutes, which we had to count out loud the whole time. After that, we had to run to try and get to another safe zone without getting tagged. Pretty simple.

We played a quick game of Rock, Paper, Scissors and determined that Chris would be It first. He gave us a two minute lead and we all took off in different directions.

Here's one thing I can tell you: I'm a pretty fast runner. At my old school, I always set records for running the 50 yard dash the fastest. So I took off, again not really paying attention to where I was heading. I figured that I would head towards the creek and hang out in that safe zone for a while.

As I ran, I began to pick up a steady pace. Chris wasn't anywhere near me. Up ahead, I noticed a girl with raven-colored hair also running. It wasn't Natalie or Jill, but I ran to catch up with her anyway.

When I was about five feet away, I recognized her. "Hey, Robin! We looked for you for ages last night."

She turned around and gave me a fleeting, troubled glance, and started running even fasted. I struggled to keep up with her. "What happened to you last night? We looked everywhere!"

"Stop looking for me. Don't look for me anymore."

As soon as she said that, she ran even faster. And right before my eyes, she vanished.

Cassie's friend had disappeared on us again. And this time, I wasn't sure who – or what – she really was.