Three twelve-year-olds are gathered in a bathroom, copying a diagram from a book onto the floor in chalk.

"Do you know what all this writing means?" asks the green-eyed boy.

"No," says the bushy-haired girl, "and that worries me too, but we need to find out who the Heir of Slytherin is and this ritual is the best we've got."

Eventually, one or another of them draws the last bit of the outer circle.