the_debt_of_time

"No! They've got a right to know everything, Sirius!" Remus snapped, ignoring Sirius's
occasional attention toward Hermione; there would be time for that later if they all survived
this. He turned quickly to Harry. "Everyone thought Sirius killed Peter; I believed it myself
until I saw the map tonight. Because the Marauder's Map never lies. Peter's alive."
"And he's right there," Sirius announced, pointing a finger at Ron.
The redhead paled. "M-Me?"
Sirius rolled his eyes. "Not you, you idiot. Your rat."
"Scabbers?" Ron protectively cupped the rat that was hiding in his pocket.
"Scabbers has been in my family for―"
"Twelve years?" Remus knowingly asked.
Hermione spoke, in a trembling, would-be calm sort of voice, "But Professor Lupin,
Scabbers can't be Pettigrew. It just can't be true."
"Why can't it be true?" Remus asked her calmly, a hint of tenderness in his voice as
though wanting to let her know that he was not angry with her for her earlier outburst.
"Because.. ." Hermione hesitated for a moment. "Because people would know if
Peter Pettigrew had been an Animagus. We did Animagi in class with Professor
McGonagall. And I looked them up when I did my homework. The Ministry of Magic
keeps tabs on witches and wizards who can become animals; there's a register showing
what animal they become, and their markings and things. I went and looked Professor
McGonagall up on the register, and there have been only seven Animagi this century, and
Pettigrew's name wasn't on the list."
"Right again, Hermione. But the Ministry never knew that there used to be f—
three unregistered Animagi running around Hogwarts." Remus took note of the incredulous
way that Sirius was now looking at him, presumably because he had caught the lie.
"Hermione, you are right that I am a werewolf. I was bitten when I was a very young
boy," he said and sighed when he saw the look of pity cross her face. "I didn't even think
I would be able to come to Hogwarts, but Professor Dumbledore pulled some strings, and
I was able to get a proper education. I was prepared to be very lonely. The Whomping
Willow was planted the summer before my first year because this shack was the designated
place for me to transform. It was set up so I could go to Hogwarts and still keep people
safe.