Its been a few weeks since you had that meeting with Dumbledore talking about the open position to teach Defense Against the Dark arts, and you had decided to take the job. It's currently September 1st, the first day of the new term, aka, the start of your job.

You're in an empty compartment on the Hogwarts Express, sitting in the seat near the window, leaning against the glass, completely dozed off, your briefcase on the ground next to your feet. The children had just started boarding, and 3 kids had entered your cabin, Hermione, Ron, and Harry. They thought it was a little weird at first, a woman in her 30's with her robes that had holes in them and faded scars all over her face and visible skin, but they eventually ignored you as you slept there, slumped against the window.