The player character, named William, mistakenly referred to as Eggs Benedict, is a new employee of the underground Circus Baby's Rentals and Entertainment, a sister company of Fazbear Entertainment featuring animatronics that are rented out to children's birthday parties; they were originally intended for use in a pizzeria called Circus Baby's Pizza World, but the pizzeria had been shut down shortly before it was supposed to open due to "gas leaks". Mike is instructed by HandUnit (an AI that helps the player throughout the game) to watch and 'turn on' the animatronics by electrifying them so they may be used during the day. He is also guided by the voice of Circus Baby, a female clown animatronic and the star of Circus Baby's Pizza World, who gives instructions sometimes contradictory to those of HandUnit. Baby's instructions help Mike survive the nights from the hostile animatronics: the ballerina Ballora and her minions known as Minireenas; miniature animatronics known as Bidybabs; and 'Funtime' versions of Freddy Fazbear and Foxy the Pirate Fox. It is implied via monologues throughout the game, as well as the ending of the 8-bit-style minigame, that Baby houses the remains of Mr Afton's daughter, who was previously killed by her in a freak accident. In between nights, as the player completes each one, a voice of a young British girl (Afton's daughter) can be heard asking her father if she can see Circus Baby. Her words imply that her father refuses to let her go to Circus Baby, and when the player obtains the death minigame, it is revealed that the girl went to Circus Baby against her father's wishes, supposedly causing her demise. As the week passes, the animatronics are taken to the parts and service room one by one due to apparent malfunction. At the end of third night, Circus Baby reveals that she kidnaps Mike, and on the fourth night, hides him in a spring lock suit just outside the "scooping room", where the animatronics' endoskeletons are forcibly removed by a machine Baby refers to as "The Scooper" (designed in a way similar to an excavator), and has Mike watch as the machine tears Ballora's endoskeleton out. On the final night, two agents sent to fix the animatronics are found hanged in the Ballora and Funtime auditoriums, respectively. After reaching the Parts and service room, Mike is told by Baby to take her to the scooping room. From there, Mike can heed Baby's instruction and obtain the normal ending, or sidetrack to the hidden "private room" and get into the alternate ending after completing Baby's minigame, where the player needs to clear a survival mission modeled after the first game for the real ending. In the normal ending, after entering the scooping room, Baby, who is now the consciousness of Ennard, reveals that she and the other animatronics have been attempting to escape the complex, but without a human guise, they are unable to. However, now that they are assembled with a sympathetic human, i.e. Mike, they have merged into a single animatronic called Ennard to take his body. The epilogue ends with Ennard locking Mike inside the scooping room and using the machine to disembowel him and take his body. The final scene of the game shows Ennard inspecting itself in the mirror while inhabiting Mike's body. In the alternate ending, after surviving inside the security office, Mike escapes home and watches the season finale of the animated series The Immortal and the Restless (whose previous episodes are shown in-between the nights and whose plot lampoons the series). After the show ends, however, Ennard appears in the room and slowly advances towards Mike.
