I found it hard to believe that Christopher, son of the Danish Prime Minister, is so easily kidnapped. He has no security, has not been warned not to get into cars with strange men, and doesn't make any fuss at all. The author probably glossed over that part in order to get the story started, and so as not to show violence.
The kidnappers are a slightly disorganised bunch of communists who want to force the country out of NATO. They don't say why NATO membership is bad for the country, they just shout about evils of capitalism and wealth ownership being concentrated. Chris quickly explains that his dad won't do anything and won't be able to do anything, and is well versed in what would need to happen - a referendum, public support, the Queen signing it into law. But by now the kidnappers have fallen out and slightly double crossed one another, so nobody wants to let Chris go in case he can identify them.
Chris is a calm and educated lad who tries to get on with the son of a kidnapper, Rasmus. In fact he's too calm, even bored, and only gets frightened when his subconscious shows him in a dream how easily bad things could happen to him. He tries to be aware of where he is being hidden and to leave clues.
The story contains some strong language and on-page drug abuse. Later there is some violence and it gets very suspenseful. This is worth a read but for older kids, and the lessons from it, such as not getting into cars with strangers, and not being brainwashed, are important for everyone, every age.