Walter is a 34-year-old insurance agent for General Fidelity of California. After years of watching clients attempt insurance fraud, he harbors a cynical attitude toward his industry and a secret desire to beat the system himself. He lives in the upper-class neighborhood of Los Feliz hills. His encounter with Phyllis Nirdlinger triggers his descent into criminal behavior, testing his professional expertise in crafting a seemingly perfect crime.

Phyllis is the wife of an oil industry manager, living in a house Walter comes to view with deep dread. She immediately inquires about taking out a secret accident insurance policy on her husband. Unrestrained in her desires and fascinated by the concept of death, she quickly exerts a powerful hold over Walter to execute her plans.

Lola is the 19-year-old daughter of Mr. Nirdlinger and his previous wife. She stands in sharp contrast to her stepmother, exhibiting honesty and modesty. She cares deeply for her boyfriend but harbors intense suspicions about her family dynamic, particularly regarding her stepmother's behavior.

Keyes is a veteran insurance agent at General Fidelity. Working in the industry longer than anyone else at the company, he possesses a rugged expertise and a deep skepticism about human honesty. He relies heavily on his gut instincts and statistical anomalies to detect fraudulent claims, making him a formidable investigator.

Mr. Nirdlinger is an oil industry manager and a client of General Fidelity. He is a straightforward businessman who remains entirely oblivious to the dangerous plots circling him in his own home.

Sachetti is a local university student working toward his degree. He drives a car that he uses as collateral for a loan, maintaining a relationship with Lola despite the friction within her family.

Norton is the president of General Fidelity of California. He is primarily concerned with protecting the company's profits and maintaining its public image as a benevolent protector of widows and orphans.

Nettie is Walter Huff's secretary at General Fidelity. She handles his messages and phone calls, unwittingly assisting him in establishing his alibis.

Ike is an insurance agent working alongside Walter and Keyes at the General Fidelity office.

Joe Pete is the night security guard stationed at the General Fidelity office.