Laminated pictorial boards.
Gwendolen Chant was obviously destined for Great Things. The cards said she was going to rule the world, though Cat, her brother, didn't see how that was possible. But everyone in Coven Street believed in Gwendolen's future, including Mr Nostrum who was tutoring her in witchcraft. So no one was surprised when the elegant stranger appear, and the two young Chants were translated from seedy Coven Street to the grandeur of Chrestomanci Castle. It was very luxurious and pleasant at the Castle and Cat would have enjoyed it thoroughly if he hadn't been so terrified by Chrestomanci himself. Who was Chrestomanci? And why where they there?