Everything you need to understand or teach The Cuckoo Sister by Vivien Alcock.
The Cuckoo Sister treats questions of personal growth, as well as identity and isolation in a family first torn by loss, then shocked by a possible restoration. Preteen Kate Seton is faced with the sudden addition to her affluent household of a lower-class girl named Rosie, who brings with her a mystery.
Either Rosie is Kate's older sister Emma, kidnapped as a baby years ago, or she is an unwanted child turned over...