McGonagall: I need to leave early.
Sprout: Detention with Potter and Black again?
McGonagall: *sighs* Yes. Thank Merlin for Lupin’s good influence; without him I wouldn’t have any free time at all.
-Meanwhile in the Gryffindor common room-
James: So you’re saying there’s a spell that will turn the Slytherin robes red and gold?
Sirius: Yes! I was thinking tomorrow at dinner-
Remus: Absolutely not!
Sirius: Aw, come on Moony! It’s harmless.
Remus: You will not be turning the Slytherin robes red and gold.
Remus: Not when there’s a spell that will make them see-through.