He turned around and wrote the first sentence on the blackboard.
[An extremely irresponsible, high-risk gathering]
Then he drew a huge cross through it with the chalk.
Beside it, he wrote the real translation.
[We didn't receive an invitation, and we can't get anything out of it, which makes us look bad.]
Sharp intakes of breath sounded around the office.
Sirius did not stop.
He wrote the second sentence.
[A threat to the "International Statute of Secrecy"]
Another enormous cross.
The translation beside it was even more blatant.
[This is an excellent pretext for putting pressure on the public and the Wizengamot, making us look busy, and applying for some funding while we're at it.]
Lupin stared blankly at the blackboard.
The despair on his face began to crack.
Finally, Sirius wrote down the most devastating threat.
[Dispatch elite Hit Wizards to enforce supervision]
He drew the cross so hard that the chalk snapped in two.
He tossed away the broken stub, took a fresh piece, and wrote the final answer in handwriting steeped in mockery.
[We want to send people over, but we need something to call it, like a "security consultation fee" or a "special operations allowance." You understand.]
He tossed the chalk aside and dusted off his hands.
Then he turned to face the dumbstruck Lupin.
"See, Moony."
His voice brimmed with the Black family's inborn arrogance, the kind that saw right through the rules.
"This isn't a warning letter."
"It's a bill disguised as a threat."
"That old fellow Scrimgeour doesn't want to cancel your party at all. He wants in, and he wants a cut."
Sirius walked back to the desk, braced both arms against its surface, and leaned forward, fixing Lupin with a burning gaze.
"Remember, Moony, every letter in a Ministry of Magic