A neighbor's young, second wife is more romantically interested in her stepson than her husband. Her jealousy of Audra, the stepson's childhood sweetheart, leads to a shooting-and puts Audra in danger from the husband.
Audra has a budding relationship with a young man on a neighboring ranch. The young man's beautiful stepmother also has a strong romantic interest in the young man. The jealous stepmother makes several unwanted advances to the young man. She then tries to warn Audra off, and when this fails she personally confronts Audra. During a heated argument the stepmother grabs a pistol and attempts to "accidentally" shoot Audra. A struggle ensues and the stepmother is herself accidentally shot dead. The woman's husband is understandably upset at his wife's shooting, but at length the truth comes out that the stepmother had caused the entire situation and there was no one else to blame. Everyone is forgiven and life goes on in the Big Valley.