Everything about Lemmie Ferguson's life is bright and shiny and sunny - her special way of looking at the world means she sees it in vivid, rainbow-hued technicolour. Lemmie's eighteen-year-old sister, the spontaneous, sparkly Rose Rouge, calls it marshmallow magic...But there's a dark spot in Lemmie's life, and with the return of her primary-school rival, Sian, even the old marshmallow magic doesn't seem to be working. Lemmie needs her special sister more than ever, but can she count on Rose when she needs her the most?