The Harried Heroes of Hogwarts

Hermione doesn't know why she's suddenly seeing names and numbers floating over people's heads. Neither do Terence, Penelope and Cedric. When four children are dragged into a world of quirky quests, and dangerous dungeons there is only one thing they can do: play the game. But what good are four reluctant, overconfident heroes against a long line of increasingly powerful villains?