I may not be up to date with the lore, but...
Allow me to rant here for a moment before I fully explain the story. Im going based off the info i know and have gathered. Fnaf 2 was a prequel and fnaf 1 was a sequel. And so the fnaf 2 place opened in 1983. The withered animatronics were being used for parts. Until the murders at the fnaf 2 place happened and it closed down. And then fnaf 1 place opened up in 1987
AAANYWAYS...
The story starts with 4 kids(Susie,Fritz,Jeremy and Gerald). All who are friends eager to explore the pizzeria.
There's Toy Bonnie, Toy Freddy, Toy Chica, and Toy Foxy (which we all know what happens to him). After their performance, the three main animatronics step off stage to wander around and interact with other people.
Of course, in prize corner, is Marionette. It is by the prize counter handing out prizes to the kids. And in the game area, the beloved nuisance, Balloon Boy. In the day, it's all fun and games.
But at night, Jeremy Fitzgerald is on night guard duty. Losing his ming over animatronics coming to life at night.