"Magical people have a sort of energy that can be detected," Cedric started. "I don't have all of the answers, but it's how we're given invitations to go to Hogwarts. They can sense when a magical child is born. And there are traces placed on us to monitor when we use magic. It's illegal for a wizard in training to cast magic away from Hogwarts until they turn seventeen, and we receive warnings if we do."

He was interested in that, of course. Muggles really were clever, weren't they? "I'm amazed by what they've built. But---wait, you see magic? What does that mean, exactly?"