Five Nights at Freddy's 3 is set thirty years after Freddy Fazbear's Pizza closed its doors and is torn down.^[4] The player assumes the role of a newly hired employee at Fazbear's Fright, a horror-themed attraction based on the unsolved mysteries of Freddy Fazbear's Pizza, constructed using artifacts and remains salvaged from the original restaurants. During the week before the attraction is scheduled to open to the public, the player must watch over the facility from the security office during the night shift (12:00 am to 6:00 am game time), using a network of surveillance cameras placed in the rooms and air vents.^[5] In addition, the player must monitor the status of three operating systems — cameras, audio, and ventilation — and reboot them whenever they begin to malfunction. Camera problems cause the video feeds, already poorly lit and distorted, to become totally obscured by static. System failures can occur on their own or be triggered by the appearance of phantoms of animatronics from the previous games.

After the first night, the staff at Fazbear's Fright uncover a deteriorated, heavily damaged rabbit animatronic, which they refer to as Springtrap. The player must now prevent it from entering the office and attacking; if this happens, the game ends. The player can seal off the air vents at certain points to block its progress, but cannot seal the door or air vent that lead directly into the office. The audio system can be used to play sound effects that draw it away from the office.^[6] If the ventilation system fails, the player's field of vision begins to fade, allowing Springtrap to reach the office and attack more easily; the player may also begin to hallucinate seeing more than one Springtrap on the video feeds before the real one may attack.

As the nights progress, the player hears a series of instructional cassette tapes, similar to the telephone calls from the first two games, that instruct employees how to operate the Springtrap suit, which can be worn by both humans and animatronic endoskeletons. However, later tapes discourage usage of the suit by employees due to a series of fatal accidents involving the failure of the suit's spring-lock mechanism.^[7] Low-resolution minigames between nights hint at the restaurant's troubled past, with the first four nights' minigames depicting the original animatronics following a dark purple animatronic before being violently disassembled by a 'purple man', previously seen in the minigames of Five Nights at Freddy's 2, as the man responsible for the various murders that occurred throughout the franchise's history. In the fifth night's minigame, the ghosts of the five children who inhabited the animatronics corner the purple man, who attempts to protect himself by hiding in the Springtrap suit. However, the suit's faulty spring-lock mechanism fails, and the purple man is crushed as the children fade away, leaving their killer to bleed to death.^[8]

Unlike the previous entries, Five Nights at Freddy's 3 contains two endings, depending on whether the player has found and completed all of the hidden minigames within the main game. Some of these are only available on specific nights, while others can be accessed during any night. The "bad ending" is attained from completing the game without completing all the hidden minigames, and shows a screen depicting the heads of the five animatronics from the first game with lit-up eyes, showing that the ghost children are still trapped. Completing all the hidden minigames before completing the game earns the "good ending", which is the same screen as described previously but with the animatronics' heads turned off, indicating that the ghost children are freed.

Completing all five nights unlocks a bonus night, "Nightmare", which boosts the game's difficulty, similar to "Night 6" in the previous titles. While playing the mode, an archived recording states that all Freddy Fazbear Pizza locations' safe rooms, an additional emergency room not recorded in the animatronics' AI or security systems,^[9] will be permanently sealed, instructing employees to tell no one of their existence.^[10] When this night is completed, a newspaper clipping reveals that Fazbear's Fright is destroyed in a fire shortly after the events of the game, and that any salvageable pieces from the attraction are to be auctioned off.^[11] However, brightening the image reveals Springtrap in the background, which suggests he somehow survived, leaving his fate unknown. i own nothing its from wiki