Samantha Stephens (Patricia Kalember) seems to have the picture perfect life - a great career as an illustrator, a successful surgeon husband and two beautiful children, but beneath the surface everything is not OK. She is unnerved by a recent sense of paranoia and believes a mysterious stranger is following her everywhere. When her daughter Molly's (Keely Purvis) grades begin to plummet, Samantha arranges a meeting with Molly's new teacher, Victoria Paige (Erika Eleniak). Samantha is immediately captivated by Victoria's sharp wit, beauty, and passion for education...so much so that she hires Victoria to tutor Molly at their home after school.

The entire Stephens family is immediately won over by Victoria. Molly's grades improve and Victoria's increased presence around the house provides some much needed stability in Samantha's life. Not everyone is charmed by Victoria, including Samantha's neighbor and best friend Jane (Lori Triolo), who questions Victoria's intentions. Samantha dismisses Jane's suspicion as jealousy over her new constant companion and her relationship with Victoria continues to grow.

Soon Samantha's paranoia increases after she is haunted by a series of foreboding incidents, including prank phone calls with strange signals, missing household items, mysterious family illnesses and a midnight intruder. In her fragile mind state, Samantha is unsure who is responsible - could it be Victoria, a possessive Jane, the mysterious stranger or just a figment of her overactive imagination?