On a Thursday afternoon halfway through September, after a particularly nasty class in Defence Against the Dark Arts, Snape asked Draco to remain behind. Once the last student had left, he was surprised to find Granger entering. Snape had given a pretence of talking about something the Head Boy and Head Girl should know or do. Knowing his head of house, Draco instantly knew that was not the case and he had a feeling Granger knew too, the way she fiddled with the hem of her robes.