"Cath is a Simon Snow fan. Okay, the whole world is a Simon Snow fan, but for Cath, being a fan is her life - and she's really good at it. She and her twin sister, Wren, ensconced themselves in the Simon Snow series when they were just kids; it's what got them through their mother leaving. Reading. Rereading. Hanging out in Simon Snow forums, writing Simon Snow fan fiction, dressing up like the characters for every movie premiere. Cath's sister has...