The new novel by Carnegie-nominated author, Barbara Mitchelhill.      Sam Pargeter and his younger brother and sister have always been poor. But, in their tiny house in the country, with Ma and Pa, they were one big happy family. Until Pa goes off to America to seek their fortune and Ma dies. Then the Pargeter children find themselves whisked off to live with a strange aunt and uncle, and are put to work -- just like Oliver Twist in their favourite book.      But this is only the start of the twists and turns their lives will take. Sam, Eliza and Alfie make their way all over London and then beyond, in search of their only remaining member of family: a rich grandfather they have never known.