Chapter 1
At 2:13 a.m., Mara's phone lit up.
The sudden glow cut through the darkness of her bedroom, bright enough to make her squint.
She groaned and reached blindly across the mattress.
For a few seconds, she considered ignoring it.
Who sent a message at two in the morning?
Her hand finally found the phone beneath her pillow. She pulled it out, expecting to see Lena's name.
Instead, there was an unfamiliar number.
Mara frowned.
She unlocked the screen.
There was only one message.
DON'T OPEN THE DOOR.
She stared at it.
Then she laughed.
It wasn't particularly funny. More of a tired breath that escaped her because the alternative was wondering why some stranger had decided to send her a warning in the middle of the night.
"Very funny," she muttered.
She dropped the phone beside her and pulled the blanket higher.
The apartment was quiet.
Too quiet, perhaps, but Mara was used to the nighttime sounds of the building. Pipes groaned occasionally behind the walls. Someone on the floor above sometimes dragged furniture around at ridiculous hours. The old refrigerator in the kitchen made a low humming noise whenever it kicked on.
Tonight, however, there was nothing.
Mara closed her eyes.
A few seconds passed.
Then came three knocks.
Tap.
Tap.
Tap.
Her eyes opened.
She didn't move.
The sound had come from the front door.
Mara slowly pushed herself upright.
For a moment, she simply listened.
Nothing.
She checked the time.
2:14 a.m.
Her heart began beating harder.
Probably a neighbor, she told herself.
Maybe someone had gotten the wrong apartment.
Then her phone vibrated.
Mara flinched.
She grabbed it.
Another message.
Same number.
DON'T OPEN THE DOOR.
Her stomach tightened.
This time, she didn't laugh.
Another three knocks came from the hallway.
Tap.
Tap.
Tap.
Mara's fingers tightened around the phone.
"Who's there?"
Silence.
She immediately regretted speaking.
She should have stayed quiet.
She should have pretended nobody was home.
Instead, she heard a familiar voice from the other side of the door.
"Mara?"
Her blood went cold.
She knew that voice.
"Lena?"
Her sister.
Mara stared at the door.
Lena was supposed to be out of town.
She had called Mara earlier that evening, complaining about her bus being delayed and promising she would text when she arrived.
Mara had fallen asleep before that happened.
She looked at her phone again.
No missed calls.
No messages from Lena.
Nothing.
"Mara," the voice called again.
It sounded exactly like her sister.
"I'm outside. Open the door."
Mara slid out of bed.
Her feet touched the cold floor.
She took one step toward the bedroom doorway.
Then stopped.
Her phone vibrated again.
This time, Mara almost dropped it.
She looked down.
A new message had appeared.
Four words.
THAT ISN'T LENA.
Mara stopped breathing.
For several seconds, she couldn't move.
Outside, Lena knocked again.
Three gentle taps.
Tap.
Tap.
Tap.
"Mara?"
The voice sounded concerned now.
"Please open the door."
Mara backed away.
"No."
Her voice was barely audible.
The thing outside laughed softly.
It was Lena's laugh.
That made it worse.
Mara hurried back toward the bed and locked the bedroom door behind her.
She knew it wouldn't help.
The front door was already locked.
But she needed something between herself and whatever was standing outside.
Her phone vibrated.
Mara looked at the screen.
WHY DID YOU LOCK THE DOOR?
She stared at the message.
Her hands began to shake.
She hadn't told anyone she had locked the bedroom door.
She hadn't called anyone.
She hadn't typed anything.
Another vibration.
I CAN SEE YOU.
Mara slowly looked around the bedroom.
The curtains were closed.
The wardrobe doors were shut.
The bathroom door was open.
Her desk sat exactly where it always did.
Her bed.
Her lamp.
Her bookshelf.
Nothing moved.
Nothing looked wrong.
"Mara?"
Lena's voice came from the hallway again.
"I'm getting worried."
Mara covered her mouth.
The voice was perfect.
Every little detail was right.
The softness.
The rhythm.
Even the slight way Lena dragged out Mara's name whenever she was annoyed with her.
But Lena wasn't there.
Mara knew that.
She knew it with the same certainty she knew her own name.
The phone vibrated again.
Mara looked down.
There was no new message.
Instead, the previous message had changed.
I CAN SEE YOU.
The words disappeared.
A new message appeared beneath it.
LOOK BEHIND YOU.
Mara froze.
She didn't turn around.
She couldn't.
Her eyes remained fixed on the phone.
Her breathing became shallow.
Slowly, painfully slowly, she raised her eyes toward the dark reflection in the window.
At first, she saw only herself.
Then she noticed something behind her.
A shape.
Tall.
Still.
Standing in the corner of the bedroom.
Mara's blood ran cold.
She spun around.
The corner was empty.
Her phone slipped from her hand and landed on the mattress.
She stared at the space.
Nothing.
Absolutely nothing.
Then her phone vibrated again.
Mara looked down.
A new message appeared.
YOU SHOULDN'T HAVE LOOKED.
Outside the bedroom, something creaked.
Mara slowly raised her head.
The bedroom door was still locked.
But the handle was moving.
Once.
Twice.
Then it stopped.
Silence filled the room.
And from the other side of the door, Lena whispered:
"Mara..."
A pause.
Then, in a voice that was no longer pretending to be afraid:
"Why are you hiding from me?"
Mara backed away from the door.
Her phone vibrated.
She looked down.
There was no number this time.
No contact name.
No notification icon.
Just a message.
I'M NOT OUTSIDE.
Mara stared at the words.
Her heart hammered against her ribs.
Another message appeared.
I'M INSIDE.
