The novel likely belongs to the mystery or thriller genre, given the authors' background in creating detective and crime fiction. It may feature elements of suspense, intrigue, and adventure, as well as a complex plot involving political intrigue, deception, and betrayal.As the title suggests, "A Royal Prisoner" may involve a member of royalty who finds themselves imprisoned or otherwise entangled in a dangerous situation. The protagonist, whether the royal figure themselves or someone tasked with rescuing them, may face numerous obstacles and adversaries as they navigate the treacherous world of palace politics and power struggles.Overall, "A Royal Prisoner" is likely to offer readers an exciting and fast-paced narrative filled with twists and turns, as well as a glimpse into the authors' creative imagination and storytelling prowess. It may appeal to fans of classic mystery and adventure fiction, as well as those interested in early 20th-century French literature.