This story is a bit like the ocean: excitement, danger, and cluelessness as to what's coming next.
Peter and Elise Anderson's friend, Henrik Melchior, hears about a sunken Nazi treasure and he wants to strike it rich. While inspecting a suspicious boat owned by Germans, the kids end up being stowaways and prisoners on the high seas. Unsure of what will happen to them, they must work together to find a way to escape back home to Denmark.
Even though Peter wants to find the treasure, he realizes that the treasure isn't nearly as important as his family, friend, and their survival. Elise doesn't wish to be involved in spying on the strange men or in finding a treasure that may not exist. Henrik still has his penchant for starting and being involved in some kind of trouble, though he doesn't do it intentionally. All three look out for each other and worry about their families. They are grateful for the friendliness of a German teenager even though they're suspicious of his reasons; they also help him out in a small way and he returns the favor. Henrik covets the treasure for most of the story (as do their captors), though he sees the light in the end.
Peter prays. Elise asks Henrik if he prays. Peter and Elise go to church with their grandfather; all three hope and pray for Henrik and Mr. and Mrs. Anderson's salvation. Grandfather Anderson quotes a verse. After a comment from Henrik, Peter resolves to change his partial hiding of his faith. Henrik is a Jew and has a Star of David necklace.
Two boats hit mines, but no one is injured. Two vessels sink (one intentionally). The kids nearly drown and are threatened a few times. Torpedoes are fired and water-bombs are dropped. Two men have a fight. Peter and Elise fall a few times and one man intentionally sends Peter into a dangerous situation. The crew suggest having "target practice" on some dolphins but the kids manage to drive them away.
Drug and Alcohol Content
Crude or Profane Language or Content
Perhaps unrealistic at points, but the characters are easy to sympathize with and the story is alive and exciting with its high hopes and close calls. At the end, there's a brief blurb concerning Nazis having stolen priceless treasures when they took over a nation.