"Yeah, I could think of one," says James, looking up from his writing to peer at her from over the rims of his glasses (which have slightly slipped down his nose).

"Following the textbook, exactly to a 'T'. I'd have to object to that.

"Because then I'd have to wonder whether you were you at all. Or if someone had somehow managed to brew a very potent Polyjuice potion and impersonate you instead."