The Clue in the Diary by Carolyn Keene

The book opens with Nancy, Bess, and George leaving a carnival where they met a young child, Honey, and her mother. The are on their way home when they witness a house bursting into flames. While making sure everyone is out of the house, Nancy meets a young man who is at first suspicious looking, but then she realizes is helping people. He introduced himself as Ned Nickerson. 

But that is all within the first part of the book. There is a missing father (Honey's), a man who has been duping inventors (and the owner of the house that burned), and a number of instances where Nancy is near death. 

I vaguely remember reading this as a child and enjoying it, but it is harder to suspend belief as an adult. 

Three stars

Nancy Drew Mystery Stories #7

Follows The Secret of Red Gate Farm

Followed by Nancy's Mysterious Letter

This book came out in 1932

Borrowed as audiobook from Libby

Opinions are my own