Teen fiction. Perfect condition besides shelf scuffs. 
 
"Pearl and Jodie are sisters. Pearl is the younger one, small, shy and anxious. Jodie is nearly three years older, bold and brash and bad and Pearl adores her. When their parents get new jobs at Melchester College, a Victorian Gothic mansion, the girls spend a bizarre summer holiday in the boarding school with just a few leftover children for company. Things start to change now they are in their new home. Jodie has always been the leader but now it's Pearl who's making new friends. When term begins, their strange summer is over. But things keep on changing. Jodie really doesn't fit in with the posh teenagers in her class. Pearl is blossoming. Maybe she doesn't need Jodie as much as she used to. But Jodie needs her. And when the school celebration of Firework Night comes around and a tragic event occurs, Pearl realises quite how much she does need her big sister."