See Chapter One for disclaimer and details.
After casting several spells, Professor Snape turned to Harry and Draco, his nostrils flaring. His voice was low and threatening as he said, "You disrupted one of my classes for this? A protection amulet?" Almost as an afterthought, he turned and cast 'Finite' on Weasley.
"Get yourself-" Snape started to say to the bleeding boy, but was interrupted by the redhead.
"A protection charm?" Ronald exclaimed. "A bloody protection charm?"
"What did you think it was, Weasley?" Draco inquired.
Ron hesitated. "A protection charm, of course," he said, trying to cover his tracks.
"Your concern for Mister Potter's welfare is touching," Snape's voice drawled. "And how did you come by this amulet?" he asked, his face now showing a degree of suspicion as his curiousity overrode his irritation with his Slytherins. The boy was definitely trespassing where didn't belong, after all. And gifting someone he was constantly at odds with, with a protection amulet? Not likely.
That's all, folks. It's abandoned, just like the summary says.