This Was Lily's Last Gift

"'Home' should go both ways..." Vizet explained. "Not only does Harry need to think of that place as 'home,' his aunt also needs to think of it as Harry's 'home.'"

"If I'm not mistaken, the method Headmaster Dumbledore used should have included a Magic Contract, and that Magic Contract would have been extremely subtle, perhaps even no more than a suggestion..."

"The concept of 'home' is very broad... Harry's aunt actually accepted Harry, and because she was his mother's older sister, Harry accepted his aunt as well... That's what I meant by subtle."

"Home..." Sirius Black sighed, unable to stop himself from looking around. His memories of Grimmauld Place seemed to be overlapping with what he saw before him.

"It sounds..." Luna blinked. "Like an egg being protected by its shell..."

"Exactly!" Vizet nodded repeatedly. "That metaphor is perfect! Because Harry's mother was gone, the magical protection she left behind was actually very fragile, just like the 'yolk'..."

"And a Magic Contract is actually extremely stable. Without a doubt, it could become that kind of 'shell' and preserve the magical protection... That's roughly what I mean."

"So that's what you meant..." Sirius Black looked astonished. When Dumbledore had revealed the secret of the "magical protection" to him, he had used a similar metaphor.

Only Dumbledore had compared the "magical protection" to candy. To keep candy from being contaminated by dust, it always needed a layer of candy wrapper to protect it;

If the magical protection was the "candy," then the Magic Contract with Harry's aunt was the "candy wrapper" used to preserve the magical protection.

"That was how Headmaster Dumbledore put it back then..." Sirius Black tried to repeat it. "This was Lily's last gift..."

"The situation was urgent at the time. All I could do was protect it