Linda has a seemingly perfect marriage with her rough and handsome husband Mark and a lovely 8-year-old daughter Chloe. But when Chloe was injured by an elderly nanny who had fallen into dementia, Linda wanted to ensure that her child would never be hurt again. At first, the new nanny Heather seemed like an ideal addition to this almost perfect family. But Heather is a conspirator who exploits the rift in Mark and Linda's relationship and is pleased with the resulting chaos. Linda later realized in horror that Heather's intentions went far beyond the scope of the prank.