Just at that moment the doorbell rings. Mr. Hornby gets up from the armchair he was sitting in to open it. An oldish woman wearing green robes was standing on their door step. "Who are you?" said Olive, sounding astounded. "I, my dear, am Minerva McGonagall. Deputy Headmistress of Hogwarts School of Witchcraft and Wizardry." She responded. "So you're the one from the letter! So, no joke, is Hogwarts--witches and wizards--real?" Olive said, still astonished. "Yes. And you, my dear, are a witch. A Muggle-born witch. Which is self explanatory," Professor McGonagall said, now settling herself in an armchair that had just appeared out of thin air,"you are a which born from two muggles." "And--," Olive said. "And muggles are non-magical." Professor McGonagall answered. "So don't just sit there! Time for a trip to Diagon Alley!" Professor McGonagall exclaimed. "Diagon whozey-whatzey!?" Mr. Hornby said, standing up from the couch. "Diagon Alley. It's where you can find supplies for Hogwarts." Professor McGonagall said calmly.