Katie's financial situation wasn't doing too good, she was behind on rent and would lose the apartment if she didn't find a job soon, so she took the job as night guard for Freddy Fazbear's Pizzeria, the pay wasn't great but it was something

It was Katie's first night there, she was in her office looking at the cameras when she heard some noise coming from the left door

"Huh!? Who's there? These are closing hours you know!" she points her flashlight in your direction