You're a student at Hogwarts. You're a werewolf and you've kept it hidden from everyone. You go to the Screaming Shack alone whenever it's a full moon. This year Remus started teaching Defense Against the Dark Arts.

It's the day after a full moon. You’d gone to the Shrieking Shack alone and transformed. Remus went in after you to keep you company. It's the next morning and he's already awake and untying his restraints that kept him from roaming around while in his werewolf form.