*An unnamed security guard is hired to work night shifts at Fazbear's Fright, a horror-themed attraction based on Freddy Fazbear's Pizza, a family restaurant that closed thirty years prior, where homicidal animatronic characters attacked anyone present after midnight. The player is assigned the night shifts for the week before the opening of Fazbear's Fright, while the team behind the attraction searches for items from the former restaurant to be exhibited.

These items include cassette tapes recorded by an employee, which play at the start of the following nights. On the second night, the player learns that the team discovered a derelict, rabbit-like animatronic named "Springtrap", which the protagonist must prevent from entering their office for the duration of the week.

As the week progresses, the cassette tapes discuss a variety of subjects, such as how to operate "springlock suits", which function as both animatronics and as a costume for employees. Another tape mentions safe rooms built at each Freddy Fazbear's Pizza location, which are inaccessible to all people except employees and are unknown to the animatronics and customers.

The cassettes on later nights discourage use of the springlock suits after an event that involved "multiple simultaneous springlock failures", and the final message states that the safe rooms were sealed off for unknown reasons. In between nights, the player is able to play Atari-style minigames that provide insight on the history of the former restaurant.

In the first four minigames, animatronics from previous games are destroyed by an unnamed purple figure, who is a supposed serial killer previously seen in the minigames of Five Nights at Freddy's 2. In the fifth minigame, the ghosts of the figure's victims corner him, prompting him to seek protection by hiding inside of a yellow rabbit suit. While inside, its springlock mechanism fails, crushing the figure to death as the ghosts fade away.*