Books like How to Disappear Completely and Never Be Found

You know how it is when you stumble across a book you've never heard of by an author you've never heard of and you start to read and can't put the book down....?Well this is one of those books. Sophie and Margaret are two lonely sisters living a strange half life with a severely depressed mother who most of the time hardly notices their existence. One day she springs to life, briefly, and takes them off to a mysterious house which she does not allow them to enter, but in the grounds of which she deposits a For Sale sign. But Margaret is pretty sure the house is not empty. And the boy next door knows something too. But their mother takes them back home with no explanations and returns to her torpor. Thus begins a most curious, exciting and dramatic tale, with a satisfying ending. This story is probably aimed at lower teens but I read it with great pleasure and the story will stay with me for a long time.