The Secret of Red Gate Farm (Nancy Drew, Book 6) by Carolyn Keene

Nancy with pals, Bess and George, help new friend Millie's grandmother keep her farm by being boarders for a part of the summer. Before long, the gang is investigating the goings on of a cult renting part of the property, Nancy is accused of passing counterfeit money and a mysterious woman doesn't accept Nancy's help.

I think I read all of these books when I was younger. I tried to read it as a child of today to see if it would still be relevant. Some of the language is out dated but the pace was quick and the story was still engaging. I am amazed at how strong Nancy is considering this was written in 1931!

Keene, C. (1989). The secret of red gate farm. New York, NY: Grosset and Dunlap.
ISBN: 0448095068
No illustrator credit listed