In Back Roads , Amber is a sexually-maniacally-abusive 16-year-old girl .
Harley forgoes his college education , working dead-end jobs to pay the bills and raise his siblings , including his rebellious , promiscuous & sexually-maniacally-abusive 16-year-old sister , Amber ( Nicola Peltz ) .
Back Roads -LRB-2018 film-RRB-