Good history, but rather ramped up on the language and sexual content.
Plot
What happens when you have two men in a World War II prison camp, bored out of their minds, and nursing a desire to go home? An escape plan, of course. And what do you get when they want a new-yet-classic way of getting out? In effect, a modern Trojan horse.
Morality
Peter and John care for each other and other prisoners are cautious for the sake of their escape plan. Peter and others bribe and blackmail a guard.
For obvious escape reasons, Peter and John take illegal and dangerous risks.
Spiritual Content
Peter refers to a pub as his "spiritual home".
Some prisoners sing a hymn for "choir practice". Mention of something being "too much in the lap of the gods".
Violence
Mention of war- and escape-related injuries. Passive memory of the fighting the night Peter was captured. Peter and John have a couple close calls with guards. The Danish Resistance is said to have killed some Germans and worked on sabotage. An old woman is roughly jostled by railway police.
Drug and Alcohol Content
Peter is definitely a drinker, though we never see him drunk. Danish sailors pass around a bottle of schnapps. Peter and John drink beer in cafes (though never in excess). A couple people they see are definitely drunk.
Sexual Content
The diggers go naked for tunnel purposes; nothing explicit. Mention of men sunbathing naked.
At one point, Peter and his roommates talk (non-explicitly) about sex (which they clearly enjoy). Later mention of homosexuality, though not of it happening in the camp.
One man gives Peter and John the address to a brothel that may be able to help them out (they never enter). Peter tells a joke in which a man tells someone that "yours is the first attractive back I've seen". A drunk man tries to fawn on a barmaid and makes an "obscene gesture" when pushed away.
There's an instance of a (drunk) man and his wife making love (his hands are on her thigh and neck, her shirt is rather see-through, but otherwise, nothing explicit).
Crude or Profane Language or Content
Many improper uses of God's and Jesus' names. Uses of "muck" (perhaps a stand-in for the f-word?), the British version of "a**", "d***", "bas****", "b****", "h***", and the British "bloody". One Brit is said to wake up every morning cursing the Germans.
One man "breaks wind", much to the disgust of another. Mentions of some harmless jokes played on another prisoner.
Conclusion
A good inside look at a piece of history with excellent narration. However, it is highly advisable to keep this out of children's reach.