The Lost Sister of Harry Potter

AU.OC/CW, JP/LE. Cassie,the older sister of Harry, lived a good life and was blessed with a younger brother when she was five.On Halloween 1981 she lost everything she knew. Starting a new life in America, She learned to control her powers and live a normal life. When it's revealed that not everything was as it seemed on that halloween, can she return home and pick up the pieces?