After the death of her husband, Sylvia Russell becomes the head of the family's successful shoe manufacturing business. She becomes increasingly manipulative and power-hungry, using her influence to control her children and colleagues.
Sylvia's daughter, Carol, is in a loveless marriage with an older man, Hugh. Sylvia, wanting to break them apart, sees an opportunity when she discovers that their servant girl, Sally, has a crush on Hugh. She manipulates Sally into seducing Hugh, effectively ruining their marriage.
Meanwhile, Sylvia's son, Peter, is under his mother's control as well. He is a weak-willed and easily influenced man who does whatever his mother asks of him. Sylvia sees Peter as a pawn in her plan to expand the family business and increase her wealth and power.
As Sylvia becomes more ruthless in her pursuit of success, she starts an affair with her husband's executive friend, David. She sees David as a way to further her goals and increase her social standing. However, when her husband begins to suspect her infidelity, Sylvia takes matters into her own hands.
In a shocking turn of events, Sylvia poisons her husband in their quiet English manor, framing his death as a tragic accident. She then sets her sights on marrying David and taking full control of the family business.
The movie explores themes of power, manipulation, and the lengths some people will go to in order to achieve their goals. The character of Sylvia Russell is a complex and cunning antagonist who will stop at nothing to get what she wants.