Note: This review is of the out-of-print, original brown tweed book, not one of the newer rewrites. If you want to buy this book new then you can buy the Applewood reprint.
A group of excellent counterfeiters is sending their fake money all over the country. The Hardy boys' dad, a world-famous detective, thinks that the counterfeiters' base is somewhere in Bayport. Could it have something to do with the mysterious old mill?
Morality
The villains do bad things. Ordinary virtues such as justice and respect are strongly upheld by the good guys.
Spiritual Content
In the original (I don't think it's in the rewrites) there is a reference to Sunday school.
Violence
A boy almost drowns. The bad guys probably would have killed the Hardy boys if they had caught them spying on their counterfeiting.
Drug and Alcohol Content
None.
Sexual Content
None.
Crude or Profane Language or Content
None.
Conclusion
If you have the time and just want a quick easy
read, I recommend this book. It has good morals and lacks inappropriate content while still being an exciting book. The writing is fairly simplistic, so it may bore older readers. I read the blue cover rewrite and thought it was one of the most boring books I have ever read, but a year later I read it in the original and now it's one of my favorites; so if you're going to read this, then read the original.