My name is Adelaide Barton. My middle name, even though most people don't use it, is Charlotte.

You probably think that my parents must be really old fashioned to give me two names that are closer to character names out of Little House on the Prairie or Anne of Green Gables books than anything people near the end of the twentieth century have. It's true that my middle name is after my great grandmother, who was my mom's grandmother. You shouldn't be surprised by that, because Mom was closer with her grandmother than she was with her parents. My great grandmother was alive when I was born, but she died before I turned five, so I don't remember much about her. Firsthand, anyway. My mom could tell you a lot of stories about her, since they were close.

As for my first name? It's not after a family member or anyone in a history book. My mom just decided that she liked the name. She and my dad didn't discuss it beforehand. My dad has always said that that since she was the one who pushes the babies out of her body, she gets to choose all of our names. So, she chose Adelaide for me, and that was that.

I like my name. You're not going to find another Adelaide in my entire school, let alone in my entire grade. It's not like Sarah or Amanda or Rachel or Jessica. Those are a dime a dozen.

My Yeerk shares her name with hundreds of other Yeerks, too. Her name is Astrin 763. That means that there are over seven hundred and sixty-three Astrins who had that name before her. Probably more afterwards, too. She's from the Sulp Niar Pool, which was the first Yeerk Pool to exist outside of their home planet. Since then, there have been at least five more.

Astrin isn't old, though. Well, not old for a Yeerk. Since I'm eleven (almost twelve), almost anyone who's older than twenty is old. But, really, Astrin is about thirty-five years old, so she's younger than both of my parents.

By the way I talk about Astrin, you've probably figured out that I'm a voluntary Controller. Not that I had much of a choice. When they told me about alien slugs who were visiting the planet and needed human bodies to live in, I figured out pretty quickly that they wouldn't going to let me go once I knew the truth. So did the other five kids who were being asked to become full members of The Sharing that day.

One did try to run...but they caught him. He's involuntary, and I imagine that his Yeerk is not very nice to him, since I heard him screaming a couple of times at the Yeerk Pool. The rest of us were voluntary, at least to start with. I've only seen a couple of them in the voluntary area at the Yeerk Pool, but that could be because the other Yeerks feed at different times.

Anyway, when I agreed to let an alien slug live in my body, two humans took me to a chair nearby. One of them held my head really still, and the other one held my hand and told me-really nicely-that it would hurt for a second or so, and then it would stop. They both told me that I would lose control over my body as Astrin connected, but I could ask her for "control" afterwards.

Not all Yeerks like to share control, I realized later, but Astrin was one of the ones who did. We pretty much split it up fifty-fifty.

She's been my Yeerk for about a year, now. My parents are both "uninfested", as Yeerks call it, but my oldest sister has started going to Sharing meetings.

I mentioned earlier that I'm almost twelve years old. That's important not just because twelve is the last year before you become a teenager, but because stuff sometimes starts to happen to your body that's really, really weird.

Mom told me about sex and where babies came from when I was ten. She just sat me down one day, after I arrived home from school, and told me that she was going to have an important talk with me. It was really weird and I didn't think she was very comfortable about it. Afterwards, she asked me if I had any questions, but I didn't.

But the other talk? The one about what happens when blood just starts coming out of your body when you need to pee?

She didn't tell me about that when I was ten.

Or eleven.

I hadn't been feeling well that day. It started right after lunch, so Astrin and I both thought it must have been something I ate. She didn't want me to feel bad, so she took super tight control for the rest of the school day. I kept expecting to have to throw up, but nothing happened.

Even though I couldn't feel any pain, I knew that she could. Mostly because Yeerks can't hide their emotions from their hosts without a lot of practice, and Astrin never bothered to try with me. We were friends, at least, most of the time. Living so close together, we got on each other's nerves sometimes, but she'd never said or done anything to really hurt me.

(Am I still sick?) I asked her, for the tenth time that day.

(Yes,) was her response, and I could feel annoyance in her tone.

(Sorry.)

Like I said. Astrin never hurt me, the way some Yeerks did. But I didn't want to get on her nerves when she was purposefully preventing me from feeling my stomachache.

(It's okay, Addy,) Astrin reassured me.

Only a couple of people-and one Yeerk-can call me that.

She headed to the bathroom, and I wondered if I was going to-you know. Not throw up, but the other kind that looks gross, but you feel better afterwards.

She sat on the toilet, and when she got up, she screamed.

I screamed, too, within my head.

Because there was blood in the toilet.

Which I yelled.

(There's blood in the toilet!) I screamed.

(I know that!) Astrin yelled back at me.

(I'm dying! I'm dying!) I wailed. (I'm going to die before I turn twelve!)

Astrin took several deep breaths and then reached for the toilet paper. Began to wipe that area.

(Maybe, it's not so bad!) Astrin tried to reassure me. (Maybe, it's just a little blood.)

We looked at the toilet paper.

It was not a little blood.

I screamed again, and so did Astrin.

"I'm going to die," she stated, out loud. "We're going to die."

(We?) I asked her.

(Yes. When a host dies, the Yeerk usually dies. If I can't get us down to the Yeerk Pool, we'll both die,) Astrin explained.

(No! You can't die!) I yelled at her.

It wasn't fair that both of us should die, after all. The blood was coming from my body. She was just connected to my brain. Astrin had her own body!

(Get Mom!) I decided. (Maybe, she can get us the ER in time!)

"Mom! Mommy!" Astrin screamed.

Was Mom even home? Astrin and I had our own key, because she sometimes stayed at work past when we arrived. She'd decided last year that eleven was old enough to be able to stay home by yourself.

Anyway, Astrin was way older than eleven.

We heard footsteps.

"Adelaide? Honey? What's wrong?"

It was Mom's voice.

"I'm dying!" Astrin yelled. "There's blood EVERYWHERE!"

The footsteps got louder as Mom must have started running.

"Where are you?" Mom asked, and I could hear the panic in her voice.

"I'm in the bathroom!"

A minute later, Mom appeared. She saw us-me-on the toilet.

Astrin showed her the toilet paper with all the blood on it. "I didn't feel well today, and when I got home, I really had to go to the bathroom, and then this came out!"

Mom began to laugh.

"It's not funny!" Astrin yelled. "I'm dying!"

Mom crossed over to us and gave us a hug. "You're not dying, honey. You just had your first period. Hang on. You flush that down the toilet, and stay there. I'll get some tampax from my bathroom..."

Astrin did as Mom told her, and we stayed glued to the toilet.

(What's a period?) Astrin asked me.

(I have no idea.) Then, I added, (Haven't you had humans before?)

(Yes. Two boys,) Astrin reminded me. (I guess boys don't get periods.)

(Lucky them,) I grumbled.

Fifteen minutes later, Astrin and I were standing up. She'd changed out of my underwear, and now, we both knew how to use tampax and (when necessary) pads for when I had my period.

"My stomach still hurts," she told my mom, holding my arms around it.

My mom nodded in sympathy. "Cramps. You'll get those whenever you get your period, most likely. You can take advil for them."

"How often am I going to get my period?" She complained, sighing.

"Once a month, but it might take a little while for that to happen. I wouldn't be surprised if it takes a few months for your cycle to get adjusted," Mom explained, giving us another hug.

"Cycle?"

"Menstrual cycle." Mom smiled at us. "It means you can have babies, now."

"Mom! I'm not even twelve!" Astrin protested.

"I said could, I didn't say should," Mom laughed. "No, I expect you to wait at least twenty years before doing anything that could result in kids."

(The talk,) I reminded Astrin.

(Oh yes.) Astrin mentally recoiled at the memory.

"That's not going to be a problem," Astrin promised. "I never want to do that."

Mom laughed again. "You might feel differently when you're older."

"Mom?" Astrin asked. "Why didn't you warn me about this?"

I was glad Astrin asked. It had been on my mind ever since we found out I wasn't dying.

Mom shrugged, face reddening a little. "I didn't get mine until I was fourteen. Your sister didn't have hers until then, either. I figured I had at least another two years before we needed to have that talk."

(Clearly not,) Astrin told me, rolling her eyes at me.

I rolled my eyes back at her-mentally, of course.

"It would have helped to know," Astrin grumbled, just like I would have. "I thought I was dying. What if you hadn't been home? I would have had to call the police, and then, this would have been on the news."

Mom gave me a kiss on the top of my head. "I'm sorry, Addy. You're right. The important thing is that you're okay." She took our hand. "Come on. I'll take you out for ice cream. Just us."

(A bribe,) I noted. (Not to tell Dad.)

(Yes, clearly,) Astrin snickered.

"Can I have a double scoop?" Astrin asked.

"Sure," Mom agreed.

Astrin and I shared control while we ate the ice cream, or tried to. I decided that the cramps were bad enough that it wasn't worth being able to enjoy the ice cream, so Astrin went back to controlling me really tightly.

(Thanks,) I sighed. (That was awful.)

(I'm definitely going to apply for a male host after this,) Astrin grumbled.

(What if you get an involuntary? Someone who screams at you and fights you for control?) I challenged.

She sighed. (We'll see.)

The next day, I asked for control again.

(Your cramps are still pretty bad,) Astrin warned me.

I wasn't sure I believed her, since we'd taken pills for them the night before, and everything had been okay then.

(All right. Go ahead,) Astrin answered.

I only lasted a minute before begging her to take back control, which, of course, she did.

(I did warn you,) Astrin told me, rolling her eyes at me.

(Sorry. I should have believed you,) I grumbled.

Two days later, the cramps and the period was gone.

Well, at least for the time being.

(Maybe, they'll get to be less as time goes on. Doesn't your body need to adjust to this?) Astrin suggested, as I sat on my bed, reading a book.

(I hope so,) I sighed. (Boy. What do girls do who don't have Yeerks to help them?)

Astrin gave me a mental hug. (I have no idea, but maybe that's why people say they're moody all the time.)

Yeah. Probably.

The End

Author's Note:

I've had this idea for a little while-a girl getting her period for the first time, and neither she nor her Yeerk knowing what was about to happen. Even though (I expect) most girls are warned ahead of time, I can easily see a scenario in which the awkwardness of the situation and the uncertain timeline would cause parents to wait longer than they should to "warn" their daughters.

For any guys who have made it this far-I congratulate you on your bravery!