In the leafy community of Henderson, Nevada, plucky teenager Alice (Kathryn Newton) lives with her parents (Stephen Dunham, Alexondra Lee) and younger brother, Wyatt (Aiden Lovekamp).

When a single mother, who lives next door, is taken ill, Alice’s mother agrees to provide temporary refuge for the sick woman’s son, Robbie (Brady Allen).

Alice quickly realises that there is something peculiar about the new arrival and she grows concerned by the control that Robbie seems to exert over Wyatt. With the help of her boyfriend Alex (Matt Shively), who is a technical wizard, Alice rigs up cameras around her family home to spy on Robbie.