Was that a smile on his face? Almost. And then he caught himself. Any pleasure he got at seeing Remus was dashed by the way they'd parted yesterday. It still made him itch, his fingertips rubbing together as if he needed to get his wand and hex the nose right off of the Gryffindor's face.

"It's called 'research,'" Severus said, riled up, watching Remus for signs of... He wasn't quite sure to be honest. Maybe werewolves were just moody. Or maybe he had been jealous that the first real try Snape gave on the Patronus charm produced an actual result. "And what do you care?"

He got up and moved across to the other stack, slipping one book into place and taking another. He had been looking in the wrong book. He might as well try another.