Narcissa knew that this had to be business if Theodore was coming to the house on a Sunday without notice. However, she didn't know how important until the man arrived to the house.
She looked at the letter, then at Theodore. "Why does he think that you'd do what he says?" If the Dark Lord had something on Theodore, there was no guarantee that the letter was free of hexes. Then again, she doubted the man was stupid enough to hurt her in her own home. Lucius would kill him before he could reach the gates.
Taking her wand out, she checked anyway, and then she took it from him, before sitting down. She looked it over. Identify yourself to open. "Is he serious?" she asked Theodore. "I see death hasn't diminished his flare." She turned it over, and saw another writing: The cure for your grandson lies within. A ray of hope appeared inside her, but she knew better than to trust the man. Still, she had to try. "Narcissa Malfoy." Nothing happened. "Narcissa Black," she tried again unsuccessfully. "Minister for Magic." Again there was nothing. "Do you know what this means?" she asked Theodore.