While celebrating their anniversary, Linda and Mark get called home early when their five-year-old daughter Chloe gets injured while under the care of an elderly nanny. It becomes clear that a new nanny is needed, and that's when Heather enters their life. Young, gorgeous, great with kids and with a glowing recommendation, Heather seems like a godsend. But not ready to trust a new sitter, Linda sets up nanny cams. Her curiosity turns into obsession as she watches Heather slowly taking over her role in the family. Events take a darker when Heather kidnaps Chloe, and Linda finally understands why Heather entered their lives.