Each time Hermione and Draco went to the Transfiguration classroom on the fourth floor, Hermione would fiddle with the letter she had written to her parents. She knew she couldn't send it by owl, it would risk exposure. And when she had asked McGonagall at the start of term to pass it on, the old witch had looked to her with the look of someone about to tell their child there were no more sweets left. Hermione had crumbled and uncrumpled the letter in the pocket of her robes daily ever since.