My life as Harmony de la Roux

Charlotte Evans, a 22-year-old college student, encountered an accident while travelling back home. She woke up in a 5-years old body, as Harmony de la Roux, a girl who had lost both her parents in a fire outbreak. She was then adopted by Duke and Duchess Farlington, into a loving family with three sons. What is going to happen in her life now that she is an outsider in the new family?