Joanna Garner, a caterer, has good reason for being over-protective of her 16-year-old daughter Holly - reasons she has told no one. As guests begin to arrive at an exclusive party which Joanna is catering with Holly's help, there's a phone call. A hideous, disguised voice tells Joanna she must do exactly as she's told or Holly will die. Joanna desperately tries to get Holly out of the mansion, but another call from the voice reveals her every move and gives her further instructions about adding cyanide into the food she is preparing. Which one of the wealthy guests is the malevolent intruder? To complicate matters, a man Joanna is dating arrives to confront her about the past she is hiding from him. When Holly disappears, Joanna realizes she must follow the murderous directions or lose her daughter.