I try ignoring the sound. Like fingernails on a blackboard, deep and violent. It's coming from the stairs, always from the stairs.

My legs move towards my bedroom door. I can't make them stop. With each step, my heart thumps harder. Something evil's in the air; thick and musty.

In darkness, I pass my little sister's room and approach the stairway. The sound grows. Eerie light climbs up the steps and reflects off the empty wall behind the landing.

My feet round the corner and I face the stairs.

I find nothing except the steps leading down.

I breathe a deep, hot sigh.

As I start heading back, I feel something from behind. Sharp claws dancing on my shoulders.

Racing back into my room, I lock the door. Something's out there. I can almost hear the scratching sound echoing in my head.

Later that day, I can't stop thinking about it. Maybe it was just a nightmare. Ever since we moved here, I haven't gotten a decent night sleep.

Mom's making lunch in the kitchen. "Nate, you look terrible. Another bad dream?"

"I'm fine," I lie, burying my head in my Wolverine Annual.

"You're just getting adjusted to the new house."

"There's nothing new about this heap." I look at the cracked plaster walls and warped wood floors.

"It's a historical landmark. We got a great deal. We're lucky to live here."

Sure, if you can ignore the nightmares and scratching sounds coming from the staircase.

With one huge bite, I stuff the last half of my PB&J in my mouth.

"Daniel sleeping over tonight?" Mom asks.

I look over at my little sister, Mandy. She's hovering over her lunch. Her long dark hair draped over her face. And she's mumbling to herself again. The same tune over and over—something about knocking on a door. She's always been slightly off, but this house has made her worse.

"Yeah. Dan's still coming."

"I wanta friend to sp-spend the night." Mandy says, doing her best not to stutter.

"You’re too young to have a sleepover, dear," Mom reminds her.

That night, Dan arrives as Mom goes out to the garage to do laundry. We head up to my room to put a new high-performance engine in my R/C truck.

"Dang, this house belongs in one of those old black and white horror movies," Dan says as we pass Mandy's room. She's sitting with her doll, humming that stupid song.

"Let's see your new cell." I grab his phone. "What's that on the screen?" I ask, looking at hash marks across the glass.

"Nothing. It's off." I turn the phone to show him and they disappear.

"Must have been a reflection. Here, Nate, I'll turn it on."

I stop. A chill creeps up my back.

I turn the phone and it re-appears. A tic-tac-toe board—only raised like wood paneling.

"Give it here, Nate."

"Wait a sec." I hold the phone out so Dan sees the reflection. "See that?" I whisper, almost unable to breathe.

"It's just a reflection of the door behind the stairs..." Dan turns to see what I already know—there's no door. "What the-is this some sort of gag?"

We both stare at the phone's screen. In the reflection, I see panic on our faces. This is no gag.

We turn, hoping we're being stupid, that there's an explanation. But nothing's behind us except the old, gray wall at the top of the stairs. It reminds me of the scratching sounds in my dream.

"Come on. There's a mirror downstairs."

We run down, afraid to look back. I dig through some boxes that no one's bothered to unpack and find an old hat mirror.

We stand sideways on the upstairs landing, between the wall and the staircase. Slowly, with a trembling hand, I hold up the mirror.

Reflected, is an old weathered door with a tarnished brass handle all fancy and decorated. When I turn to touch it, it's gone.

"Ummm. Think I'm coming down with a cold. Your mom better take me home." Dan starts down the stairs.

"Hey, you chicken." I grab his t-shirt. "We've gotta figure this out...ourselves." There's no way Mom would believe this. Even if she did, she loves this house so much; something like this would break her heart.

I have to fix this—but how?

"Whatcha doing?" My little sister's big brown eyes stare up at us.

"Go back to your room or I'll tell Mom you're bugging us," I snap.

"Okay. Just don't open that door." She turns and heads back.

"Wait, what did you say?"

Mandy stops and stands with her back to us. Her long nightgown draped down to her feet. She starts singing that song again, only louder:

"Knock, knock on the door. Thirteen times, the monster moves no more.

Enter swiftly, don't make a sound. Except this song, the sp-specter to bound.

On a mirror, give thirteen taps. Make sure the creature can't come back.

Frame it fast, over the door. With fortunes luck, it'll be fettered evermore."

"Where'd you hear that?" I demand.

She turns around, "Don't know. Just heard it."

"That's the key, Nate, the song. It's gotta be!" Dan's voice shakes.

"Thanks for the brilliant insight. It obviously tells how to get rid of... the monster."

"Knock thirteen times. That must make it safe to enter," Dan says.

"And the mirror? Tapping the mirror must trap it."

"But can we trust a song?"

"We don’t have much choice." I look at my sister. She's gazing down at her doll. Smiling and combing its hair.

"Are we sure we got it right?" Dan asks.

Mandy repeats the song a couple of times, to make sure we got everything.

"Oaky you ready?" I ask, mirror in hand.

"No," Dan says forcing a smile.

Looking in the mirror, I reach back for the door, knocking thirteen times. The rough grain of the wood stings my knuckles, but nothing happens.

Still focused on the mirror, I grab the knob. It's ice cold.

The door opens slowly, as if pushing against me.

I turn, and now I can see the door straight on. It's open, but there's nothing except deep black beyond.

"Remember, don't say anything. I'll repeat the rhyme and tap on the mirror."

Dan's gripping my forearm so hard it hurts. I take a step into the room. The darkness is so thick it seems to press down on us. I want to turn back, but like my dream, something pushes me on.

There's a tug at my shirt, and I glance back to see that Mandy followed us in. I start to tell her to get out, when the door slams shut.

We all jump. I almost scream, but remember we can't say anything except the song. The song—what are the words to the song? I can't remember.

Everything's black. My heart beats so hard I hear it in my ears. As my eyes begin to adjust, I start to make out the room. It's dirty and coated thick with dust. Layers and layers of peeling wallpaper, a broken rocking chair, bare wires reaching down from the ceiling like long, skinny fingers.

And there's something else. Another presence--cruel, old, desperate.

Softly, a voice drifts into the air, "Knock, knock on the door..."

It's Mandy. As she repeats the song, the creature's anger swells. My arms grow numb and Dan's grip slips—something's zapping our strength.

"...it'll be fettered evermore," Mandy finishes.

It takes tons of effort to lift the mirror. Looking away, afraid of what the mirror might reveal I begin tapping.

One, two, three. I feel breath on my neck, rotten and sticky.

Four, five, six. A hissing sound fills my ears.

Seven, eight, nine. The whole room starts to rumble, like it's tearing itself apart.

Ten, eleven, twelve. The walls are closing in on us—I start to shake with panic.

Thirteen. There's a loud whoosh, and everything's silent.

I hear a click and a sliver of light slices across the floor. The door's open.

Dan quickly jumps out. I put my hand on Mandy's shoulder as we leave. The door gently clicks closed behind us.

"Good job, little Sis," I say and turn. The door's gone. Just a bare wall—except for one large rusty nail. "Wow. That was close."

I hang the mirror on the nail.

"Yeah, I thought we were dead when Mandy mispronounced specter."

"Mispronounced what?"

A crack appears in the mirror and spreads like a spider web.