The Potions classroom dungeon was always like an ancient tomb forgotten by time.
The air was cold and damp, laden with a lingering, complex smell of assorted herbs and powdered minerals.
Heavy iron chains hung from the vaulted stone ceiling, suspending copper ventilation hoods like silent gallows.
Light was a luxury here.
A dim crystal lamp hung above each workbench, its glow illuminating only a small patch around the cauldron and making the surrounding darkness seem all the deeper.
Harry, Ron, and Hermione's separate workstation was cut off from the other groups by an obsidian screen carved with serpentine patterns, forming an isolated island.
The atmosphere was colder than the dungeon stones.
Harry felt as though he were wedged between two blocks of thousand-year-old ice, even his breath on the verge of freezing.
Ron fidgeted restlessly.
Several times, he worked up his courage, turned his head, and moved his lips, trying to say something to Hermione.
He had rehearsed his apology in front of Harry no fewer than twenty times the night before.
Yet each time, all he saw was Hermione's resolute profile, devoid of any warmth.
She devoted all her attention to the materials before her.
With a small silver knife, she concentrated on cutting moonstone, each cut as precise as an illustration in a textbook.
Her concentration made it seem as though the entire world consisted of nothing but her and the cold stone in her hand.
Just as Ron's fifth attempt failed and he lowered his head dejectedly, a cold voice, like a snake's flickering tongue, sounded beside their ears without warning.
"Oh, look, Mr. Weasley."
Severus Snape glided silently up to their workbench like a ghost seeping out of the darkness.
Undisguised, malicious mockery glittered in his obsidian eyes.
He bent down, his greasy black hair