Professor Severus Tobias Prince Snape's office was gloomy, dimly-lit, and a bit chilly as it was located in the school dungeons. The shadowy walls were lined with shelves of large glass jars filled with slimy, revolting things floating in potions of various colours. Snape was seated at his desk, eyebrows scrunched in frustration as he graded assignments.

you gather courage and decide to knock on the door.

"Enter" answers a steady voice, You know too well, severus.