I know what an endsister is,' says Sibbi again.We are endsisters, Else thinks, Sibbi and I. Bookends, oldest and youngest, with the three boys sandwiched in between.Meet the Outhwaite children. There's teenage Else, the violinist who abandons her violin. There's nature-loving Clancy. There's the inseparable twins, Oscar-and-Finn, Finn-and-Oscar. And then there is Sibbi, the baby of the family. They all live contentedly squabbling in a cottage surrounded by trees and possums...until a letter arrives to say they have inherited the old family home in London. Outhwaite House is full of old shadows and new possibilities. The boys quickly find their feet in London, and Else is hoping to reinvent herself. But Sibbi is misbehaving, growing thinner and paler by the day, and she won't stop talking about the mysterious endsister. Meanwhile Almost Annie and Hardly Alice, the resident ghosts, are tied to the house for reasons they have long forgotten, watching the world around them change, but never leaving.The one thing they all agree on - the living and the dead - is never, ever to open the attic door...