the_debt_of_time

"The fake locket Horcrux that Dumbledore and Harry found had a note in it from
one of You-Know-Who's followers," Hermione explained to him. "One who defected and
stole his Horcrux intending to destroy it."
"Good for him, sticking it to old—Wait. R.A.B.? No." Sirius shook his head.
"Absolutely not."
"It fits, Sirius," Harry said.
"No," Sirius growled, remembering the last time he had seen his younger brother,
complete with Death Eater regalia. "Regulus was a Death Eater. He was a bloody idiot who
bought into all the pureblood nonsense that my parents taught us."
"Would you recognise his handwriting?" Hermione asked, reaching into her beaded
bag and pulling out the fake locket. As she popped it open, a small piece of folded
parchment tumbled out.
Sirius took it quickly and opened it, immediately recognising the script. He and
Regulus had been forced to go through penmanship lessons since the moment they could
hold a quill. As usual, Sirius had rebelled and scribbled his way through most of his early
years, only appreciating the need for proper penmanship when he began writing love letters
to girls in school. It also set his notes apart from James's, which looked like a bunch of
bowtruckles had gone swimming in an inkwell and then flopped around on a piece of
parchment. Regulus, on the other hand, obeyed from the outset—as always—and set to
prove he had the most beautiful handwriting.
"This doesn't... It doesn't prove a thing. Why does it matter? Regulus is dead and
we have a fake locket," Sirius said brusquely.
"Would you be okay with us searching his room for the real one?" Harry asked.
"Have fun. I'll be downstairs." Sirius turned and fled the landing, making his way
past the drawing room to the back door, which he popped open before pulling out the
pack of cigarettes he kept in his leather jacket. Tapping one out, Sirius reached for his wand
and used a small Fire-Making Spell to light it. He took a deep drag and exhaled slowly, as
though this one small stick would keep him from breaking.
"Sirius?"
"I'm fine, Hermione," he answered before she bothered asking. "Did you find it?"
"Not yet. Harry and Ron are still looking," Hermione replied as she approached
him.