I apologize for how disjointed this is. I haven't written in a long time, but this prompt gave me something more or less fully-formed that I had to get out of my head as quickly as I could. All criticisms, opinions and advice are greatly appreciated.

“Can you do a lubally before I go to sleep, Daddy?”

We’ve been doing this for six weeks, but I still chuckle every time she gets the word wrong. I’m not her father, but... well. I guess I am.

“Remember, it’s a lullaby, not a lubally. And yes, we can do it in a few minutes. I just have to make sure we’re all secure. How do we make sure we’re secure?”

Three months ago, I was just a guy who worked in an office. I wasn’t married. I didn’t have any kids. I worked a 9-5, went home, trawled the internet, played video games. I didn’t have any family. I didn’t make any waves. I didn’t matter.

“Check the locks on the door. Look outside to the north. If you see a glow, hide under the bed and don’t make any noise until sunrise.”

Their biology is... weird. When they first showed up, the news -- back when there was news -- was nothing but a lot of arguing about why they did what they did. Why they glowed orange, but only attacked at night. Why they only came from the north.

“That’s right. Now, did you brush your teeth?”

The xenobiologists thought they came from a planet where the visible spectrum didn’t matter. That explained why they glowed, but it didn’t explain why they only attacked from the north. It didn’t explain why they always left at sunrise. I guess there aren’t too many xenobiologists left to argue about it.

“Awww, do I have to? You said these are baby teeth and I’ll get new ones!”

When everyone started going south, I started going north. I’ve always had a rebellious streak in me, and I guess some part of me thought I’d have less people to deal with if I moved against the tide. I was afraid of how many people I’d run into, but it turns out that most people avoid someone moving towards danger. They think you’re crazy. I’m not sure they were wrong.

“You will, but it’s not just about the teeth. It’s about establishing good habits. If you don’t learn to take care of these, you won’t know how to take care of the permanent ones. I don’t know where there’s any dentists, and teeth can be a real problem if you’re not careful.”

I happened upon a gated community that didn’t seem too damaged, and started going house by house, scavenging for whatever I could find. I entered a house at random, and started walking down a hallway with a bunch of pictures of your generic happy family. Then I heard a whimper.

“What does est-estab-estabiling good habits mean?”

Through the barely there morning sun, I saw a girl sitting cross-legged on a couch. There were two men and a woman on the floor. She stared through me with a look on her face that soldiers in war movies have. The woman looked like the pictures in the hallway. She had a bullet in her head. The men weren’t in any of the pictures. They had needles in their arms.

“Es-tab-lish-ing. Establishing good habits means… it means learning to do things the right way, so that you always do them. When you establish good habits, you don’t even have to think about doing the right thing anymore. It happens automatically.”

There were maybe two dozen guns on the table and ammo to match. I almost took the guns and left. I was a 26 year old who had never even been responsible for a pet fish. She was… four? Kids all look the same to me. But she blinked. And instead of looking through me, she saw me. She started tearing up. She called me Daddy. And one of the men twitched.

“Good habits sound stupid. Why do you have to do good habits?”

I told the little girl to close her eyes and plug her ears tight. The men might have been dangerous at some point, but they were skin and bone and high off of… whatever.

“Well… I don’t really know. But you have to do good habits. Securing the perimeter is good habits, too.”

I buried the woman in the backyard. It seemed like the right thing to do. I buried the dead men in the back yard, too. That seemed like the wrong thing to do. But the aliens seemed to find human flesh a delicacy. I didn't want to draw any attention.

“Then how come I don’t ever see you brush your teeth?”

The question jolted me out of my reverie. Were all kids this smart?

“I, uh… I brush my teeth after you fall asleep.”

We met eyes, and we both giggled.

“Alright, I’ll make a deal. We’ll both brush our teeth at the same time from now on. You think about that deal, and I’ll go finish up.”

There’s no real rhyme or reason to when the aliens come, but when they do, the ground they cover… it doesn’t make sense. They seem like mindless beasts, but they show up everywhere, in numbers that defy all logic. If I didn’t know any better, I’d say they were turning our bodies into more of them, but that’s just sci-fi bullshit. Then again… I guess all of this would have been a sci-fi book, in the before times.

All of the rooms are burned into my muscle memory, and there’s no need to use a flashlight anymore. I peek through all of the windows, making sure there are no people trying to sneak up on us - although anybody crazy enough to do that at night would deserve whatever they got. My heart starts pounding as I approach the kitchen. It looks like there is a fire outside the window.

I run up the stairs as quickly and as quietly as I can, hoping against hope that she’s asleep. But she had lifted a corner of the blinds and is staring out the window, bathed in their orange light. She's shaking so hard that she can barely stand.

“Is it the boogeyman, Daddy?”

All of the guns are already upstairs. I didn’t see the point in having guns where I couldn’t see them, and she didn’t seem interested in learning about them. I had been meaning to make sure she knew how to at least clean them, because I knew having kids around guns was dangerous. But there had always been something else to do.

“Yeah. They’re here.”

I can’t see the point in trying to lie. She won't tell me about what she had seen or heard before I got here. But I know it took two weeks for her to sleep at night, and she can only sleep in my arms. How could you lie to someone who trusts you that completely?

“Is it going to hurt when we die, Daddy?”

I check my guns in the alien light, and they look like they’re on fire. I’m terrified, but my hands are steady, moving on autopilot, practicing what I’ve been practicing every day. Good habits. I hear a sound, deeper than anything I’ve ever heard. I’m not even sure if I hear it or feel it in my soul. I’m almost dizzy with the intensity of it. Then all at once, the sound is gone, but the fear is getting worse and I’m not sure if I can do this.

“W-who said we’re going to die? This is what we practiced for, remember? Now, what do you do?”

There’s no way she didn’t hear the shake in my voice. She looks at me, and I look at her with what I hope is a confident expression. She lets the blinds fall and, right before she’s about to get under the bed, I hear her pause.

“We got a brush the teeth deal, Daddy. That means we can only brush our teeth together. So we have to brush our teeth tomorrow, okay? You have to promise.”

She disappears under the bed, and just like that, the fear is gone. I hear a window shatter downstairs; I guess that sound they made let them detect us. It sounds like someone is dragging sandpaper across the floor downstairs. I close the door as quietly as I can, and make sure all of my guns are within easy reach.

“Hey, while we’re waiting, I’ll sing you a little lullaby.”

I rack my brain, trying to think of something that could pump me up and calm her down at the same time. Then, with a wry smile, it comes to me. Is the song kid-friendly? No, but I don’t think the world is kid-friendly anymore. I doubt anyone will mind too much.

“Daddy, you have to promise.”

There are certain promises that you shouldn’t make. There are certain promises that you have to make.

“I promise. Now you stay quiet. Don’t fret, precious, I’m here. Step away from the window and go back to sleep…”

Is it a lie if you believe it?

I release the safety. And I wait for dawn.