Severus looked around the library after Sirius had done talking, he was expecting a group of Black's friends to appear laughing loudly, but that did not happen. He looked at Remus and only saw seriousness there too.
"You want to apologize?" The surprise he was feeling about this was obvious on his face and in his voice. He was dreaming, that was the only explanation about what was happening. He turned to Remus, "he is apologizing?"
---
Remus could see the confusion on the Slytherin's face. He could understand the confusion, he was pretty sure that Sirius would never had apologized on his own.
"He is, and so am I." He looked at Sirius for a moment then turned back, "I don't want to think about what could have happened."