The film starts as a scared little girl, hides under a bed as a man with an axe pursues her.
40 years later, husband and wife novelists Zeke and Ashley, their young daughter Jane, Ashley's father Richard, and their dog Brooks arrive at a lakeside cabin for a vacation.
In a nearby town, they enter a thrift store where Zeke buys an old typewriter, soon noticing the name "Walter Joyce" inscribed on the bottom. Brooks starts to bark at the typewriter when he sees it.
At the cabin, Zeke is struck with inspiration for a new novel and starts to record his thoughts on the typewriter while the rest go to the lake. Immediately strange things start to happen - the paper feeder on the typewriter seems to move on its own, the carriage return snaps down on Zeke's finger, and he briefly sees a figure standing behind him.
That night, Ashley wakes in a panic, thinking an intruder is in the house - however after searching, they find nothing. The next morning, Ashley wakes up to find Zeke already typing, as more of his story came to him in a dream. After breakfast, Zeke, Ashley and Jane go for a hike while Richard stays back.
He enters the study and reads Zeke's work, but seconds after he touches the typewriter, his eyes turn black and he starts to convulse. The rest of the family return home and find Richard's body, the medical examiner assuming a heart attack.
That night, Ashley wakes up to Zeke staring out the window in a daze. Seemingly in dream state, he says he's talking to Walter Joyce before going back to bed. The next morning, Zeke suggests Ashley takes Jane into town while he makes arrangements for Richard's body.
In a town bookstore, Ashley finds a true crime book called "The Murder of Walter Joyce." She learns that Joyce was a poet who was murdered by his son, Marcius, 40 years prior, claiming his father was involved in a cult called "The Void" and was trying to kill his sister, Anabelle, who still lives nearby on a farm by herself.
They return home to find that Brooks is missing, with Zeke claiming he run away. As he searches for the dog, Ashley reads the book, learning that Joyce had supposedly contacted a demon named Ahmoz, the "Devil's scribe," who facilitated deals with the devil in exchange for a human soul. Freaked out, she throws the typewriter in the trash. Zeke returns home emptyhanded and freaks out when he learns the typewriter is gone.
That night, Ashley wakes to find Zeke standing over Jane's bed, just staring at her. The next morning, she finds that he has taken the typewriter out of the trash.
Unnerved, Ashley tracks down Anabelle's address and drives to her house with Jane. Anabelle refuses to help them and reveals she's become a hermit, having repressed much of her childhood.
Desperate, Ashley goes to the insane asylum where Marcus is held. He reveals that his father used the typewriter to literally ink a deal with the devil, thereby making the object a bridge between earth and hell. He says that the devil required the soul of "an innocent" (aka virgin) to complete the deal, hence why Joyce had tried to kill Anabelle years before.
After a silent dinner, Ashley finds Brooks' corpse in one of the trash bins outside, having been strangled with rope. She attempts to sneak out of the house with Jane, but Zeke, now fully possessed by Ahmoz, blocks the doorway. Ashley sprays him with mace and they race outside start to drive off, but Zeke gives chase with superhuman speed.
Anabelle, having decided to help them, soon drives towards the house and sees Zeke chasing, so turns around and follows. Zeke catches up to Ashley's car near a bridge in town and jumps on the roof, causing them to crash. He pulls Jane out of the car and readies to throw her off the bridge, but Anabelle arrives and begs the demon to take her soul instead of Jane's as she is still a virgin. Ahmoz leaves Zeke's body and takes hold of Anabelle, who then jumps off the bridge.
Sometime later, at the thrift shop in town, the owner of the bookstore brings in the typewriter and hands it to the cashier, both revealing they are members of The Void.