The Changeover(2017)

16-year-old Laura Chant lives with her mother and her 4-year-old brother Jacko in a poor suburb of a city in New Zealand. After some time, Laura enters into a supernatural battle with a spirit that intends to possess her brother. This creature slowly conquers his brother and by doing this he himself becomes younger. Laura discovers the true identity of the owner of this spirit and realizes his supernatural abilities. Laura has to save her brother's life by all means but...