Often, they will have a sense of mystery and suspense. The plot will revolve around the abduction, the reasons behind it, and the efforts to rescue the kidnapped person.
One common theme is power dynamics. In many kidnapping - based novels, the kidnapper often has a sense of power over the victim, whether it's physical, psychological, or both. For example, in 'The Collector', the kidnapper feels a sense of ownership over the woman he has kidnapped.
Another is 'Room' by Emma Donoghue. It involves a mother and her son who are held captive in a small room. It shows their struggle for survival and the psychological impact of being kidnapped. It also explores the bond between the mother and the child in such a harrowing situation.