the_debt_of_time

"It's not your choice, Sirius. I'm not letting anyone else die for me!"
"No one's going to die for you!"
"My parents did! You did!"
"I'm still here! And I'm doing my job for once, James!" Just as Sirius caught his
mistake, Harry caught it too. Sirius took in long deep breaths to calm himself, resting a
hand on Harry's shoulder. "I'm supposed to look after you, Harry," he said clearly. "Keep
you safe. I promised your parents. I promised... I promised to keep you safe."
The scene meanwhile played on.
"Expecto Patronum!"
From the tip of Snape's wand burst the silver doe. She landed on the office floor, bounded once
across the office, and soared out of the window. Dumbledore watched her fly away, and as her silvery glow
faded he turned back to Snape, his eyes full of tears.
Sirius could not look at it. He had known Snape's Patronus, and he had always been
a little suspicious, but his belief that Death Eaters could not possibly love kept the truth
far from him. However, seeing this... seeing the silver doe right in front of him...
"After all this time?"
"Always," Snape said.
Unable to witness anymore, Harry and Sirius rose up out of the Pensieve. Moments
later, they were lying on the carpeted floor in exactly the same room; Snape might have just
closed the door.
Sirius shook his head. "I don't know what to tell you, Harry."
"Snape loved my mother," Harry mumbled. "Do you think if he'd never called her
a―"
"No! No, she would have ended up with James no matter what," Sirius said with as
much emphasis and passion as a man defending his faith to an unbeliever. "Lily loved James,
and James worshipped Lily."
Sirius held his head in his hands. The visions of the past had not all been pleasant
ones. "One day, I'll take you back through my memories. And you can see... You can see
how they were with each other. You can see everything. I'll tell you everything."
"I'm sorry, Sirius," Harry muttered softly.
Sirius frowned. "You've got nothing to be sorry for, Harry."
"Petrificus Totalus!"