The chief engineer at the British Post Office, who mentors Marconi and supports his early experiments but later becomes his rival.

A physicist who demonstrates Hertz’s electromagnetic discoveries and becomes Marconi's rival, with an interest in the supernatural.

An American homeopath who moves to England, known for his mild manner and complicated personal life.

Crippen's ambitious second wife, who harbors dreams of stardom but faces challenges in the pursuit.

An employee at the same company as Crippen, she becomes his companion after the disappearance of Belle Elmore.

A seasoned and methodical investigator at New Scotland Yard, involved in high-profile cases such as the Crippen investigation.

A captain of the SS Montrose, known for his adventurous past and use of Marconi's wireless to report suspicious passengers.