Sky Murder

Private detective Nick Carter leads the investigation, initially declines the Senator's request but soon takes charge to protect Pat and the passengers. He uses wit and resourcefulness to uncover the spies and orchestrate a final trap that brings Cortland to justice.

Beeswax Bartholomew is Nick's loyal assistant who improvises under pressure. He disguises himself by wearing Pat's robes to fool the killers and helps execute the escape, remaining a crucial ally throughout the chase.

Wealthy industrialist and leader of the fifth-column network; he orchestrates threats against Pat's father and coordinates the attacks throughout the story. His demise comes in a shootout after a confession.

Detective and chaperone to the models, Christine assists in tracing the conspirators and supports Nick in the pursuit. She remains active in the investigation and participates in key rescuous efforts.

Model targeted by the spies; her nail file is found in Hendon's throat, marking her as a focal point of the plot. She reveals the danger posed to her father and remains central to the investigation and confrontation.

Polo star suspected of being a spy; his murder on landing triggers the investigation and escalates the peril for everyone involved.

Senator who heads the committee investigating subversive groups; he collaborates with Nick and helps uncover Cortland's plot.

A spy for Cortland, involved in the conspiracy and the kidnapping of Pat; part of the network that Nick and Christine work to dismantle.