Melissa is a dedicated mother and homemaker who is always looking for ways to keep her family happy and content. When she learns that her husband's mother has become increasingly isolated and lonely living on her own, she invites her to come live with them in their spacious home. But as soon as Grandma arrives, she starts to exhibit strange and alarming behavior.
At first, Melissa tries to be patient and understanding with her mother-in-law, but soon she realizes that something is very wrong. Grandma becomes obsessed with Melissa's daughter and starts to make bizarre statements about wanting to "replace" her own dead child with her granddaughter. Melissa becomes increasingly frightened and desperate to protect her daughter from Grandma's delusions.
As the tension in the house escalates, Melissa's husband tries to dismiss his mother's erratic behavior as just a temporary glitch, but Melissa knows that they are all in danger. She turns to an old friend, a retired detective, for help in uncovering Grandma's secrets and protecting her family from harm.
In the end, Melissa must use her own wit and resourcefulness to outsmart her homicidal mother-in-law and keep her daughter safe. The movie is a gripping psychological thriller that explores the dark side of family relationships and the power of a mother's love.
