Kill Switch by Penelope Douglas

Arion would be down at the pool for hours yet. Plenty of
time.
I walked toward the stairs, but the floorboards somewhere
behind me suddenly creaked, and I stopped, turning my head.
“Arion?” I asked.
I hadn’t heard her come in.
“Arion, are you here?” I called out again, louder this time.
Did I hear that right?
But it was silent now. No response. No more creaks. My
heart started to pump harder, though, and I listened for a
moment, my brain going through every possible scenario of
what that could’ve been.
We didn’t have pets.
My parents were gone.
I was the only one in the house.
The wind, maybe?
I clutched my phone, my thumb nervously rubbing over
the corner of the screen. “Phone,” the voice-over said as I
accidently hit the app there. I startled, picking up my foot.
As I did, though, the floor creaked again, and I hesitated a
moment before putting my foot back down on the same spot.
The floor creaked under me once again. Right at the spot I
was stepping.
Was that me then? I turned my head behind me, perking
my ear for any sounds. I could’ve sworn the sound came from
the floorboards behind me.
I put my foot down again, the old hardwood floors in our
antique home creaking under my weight as I trailed down the
stairs and into the mini ballroom.
It was fine. I just came inside, and all the doors were
locked.
I walked into the large room, counting the strides and
picturing it in my mind from my memories as a kid. A whole