Private Detective

Ex-wife of Millard Lannon and mother to his child, Mona becomes entangled in the custody conflict and is suspected after Millard's murder. She lies about her involvement at times, yet remains fiercely protective of her son and willing to take risks to survive. Her actions reveal a pragmatic, resourceful survival instinct amid a maze of lies and accusations.

Employee at the Nation-Wide Detective Agency who resigns rather than testify against Mona. She later marries Jim Rickey and becomes a crucial ally, assisting Mona and Donald as she uncovers Nat Flavin's guilt. Her integrity and courage drive the investigation forward and test her loyalty to lovers and colleagues alike.

A wealthy, controlling husband involved in a contentious custody battle whose murder triggers the central crime. His demand for police protection foreshadows the danger surrounding Mona and his son, and his execution of the plan indirectly spurs the investigation and subsequent pursuit of the true killer.

The antagonist who orchestrates the scheme to seize Mona's son's trust fund and appoint himself as her guardian. He murders Millard to silence opposition and attempts to frame Mona, using wit and manipulation to stay one step ahead of the detectives.

A police lieutenant and Mona’s fiancé who supports Myrna's investigation. He pursues the truth with determination and forms part of the team that rescues Myrna and captures Nat, balancing personal loyalty with professional duty.

Mona's intended husband and a central figure in the custody dispute. He becomes a suspect in Millard's murder but collaborates with Myrna and Mona to uncover the real killer and clear his name while defending his future with Mona.

Detective Agency employee and Jim’s assistant who joins the investigation. Brody provides practical support, helps piece together clues, and stays loyal to the mission of uncovering the truth.

Nat Flavin’s chauffeur and partner in crime, involved in the darker side of Nat’s schemes. He assists in the attempted poisoning of Mona and Donald, representing the dangerous reach of the conspirators.