"Professor, you don't look very well."
After nearly a month, Brook returned to Quirrell's office.
Quirrell looked even thinner than before, his face as pale as paper.
"I'm fine," Quirrell said hoarsely, with a hint of barely perceptible exhaustion. "How did the investigation go?"
Brook got straight to the point. "The antidote. I want a year's supply."
"You still..."
Quirrell had just started to object when he suddenly stopped speaking, his expression instantly turning extremely tense.
Brook frowned slightly.
His wand in his right hand was still pointed at Quirrell.
Meanwhile, his left hand quietly slipped into his sleeve, ready to draw his pistol at any moment.
"Only half a year's supply," Quirrell forced out. "The rest needs to be made fresh."
"Fine, but I want you to swear an Unbreakable Vow and give me the antidote formula before the operation."
A trace of surprise flashed through Quirrell's eyes. "It seems you found out quite a lot."
Brook pulled the pistol straight from his sleeve.
"Either swear the vow, or I'll tell Dumbledore. I believe that if I pay a high enough price, he can keep me alive."
Quirrell fell silent.
But from the way his body trembled, it was clear that he was far from calm.
"But without a witness, we can't make an Unbreakable Vow. Still, I can swear a Blood Oath."
"What's that?"
"A contract provided by Goblins," Quirrell explained. "Anyone who breaks it will suffer worse than death. I have a ready-made contract here. You can have it examined without exposing its contents."
"Give me the half-year supply of antidote first."
This time, Quirrell did not hesitate. He directly used the Levitation Charm to send the potion floating before Brook.
Brook did not even touch it before putting it away.
"Now you can tell me, right?"