Inspired by Kris Straub's "creepypasta" tale, season one deals with one man’s obsessive recollections of a mysterious children’s television program from the 1980s, and his ever-growing suspicions about the role it might have played in a series of nightmarish and deadly events from his childhood.

Inspired by Brian Russell’s “Creepypasta” tale, season two tells the story of Margot Sleator, a young woman who visits the No-End House, a bizarre house of horrors that consists of a series of increasingly disturbing rooms. When she returns home, Margot realizes everything has changed.

Inspired by Kerry Hammond's “Search and Rescue Woods” Creepypasta tale, season three tells the story of a young woman named Alice who moves to a new city and learns about a series of disappearances that may be connected to a baffling rumor about mysterious staircases in the city's worst neighborhoods. With help from her sister, they discover that something is preying on the city's residents.

Based on the “creepypasta” short story Hidden Door by Charlotte Bywater, season four follows newlyweds Jillian and Tom, who have each brought secrets into their marriage. When they discover a strange door in their basement, those secrets start to threaten their relationship — and their lives.