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The Secret of the Old Mill book cover

The Secret of the Old Mill

The Hardy Boys Book 3

by Franklin W. Dixon

Courier Dover Publications 2023

The Hardy Boys

Great fit for 5th grade

Reading level and content both target 4th–8th grade · ages 9–14

5th grade English Juvenile Fiction
163
Pages
7
AR Points
4.3h
Read time
AR Quiz Available

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Genre

Mystery

Themes

  • mystery-solving
  • brotherhood and teamwork
  • courage
  • perseverance
  • justice vs. crime
  • ingenuity
  • danger and suspense

About this book

Frank and Joe Hardy take on two puzzling cases that lead them to a mysterious old mill on the edge of Bayport. Strange clues, counterfeit bills, and risky chases pull the brothers into hidden passages and tight spots. With help from friends and their detective dad’s guidance, the boys use logic and courage to connect the pieces. Fast-paced and suspenseful, this classic Hardy Boys mystery hooks middle-grade readers who love clever clues and nonstop adventure.

Setting: the fictional town of Bayport and an abandoned old mill with hidden tunnels

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Frequently Asked Questions

Is The Secret of the Old Mill right for my child?

Yes — The Secret of the Old Mill is a great fit for 5th grade. The reading level is AR 5.4, which is typical for 5th grade. The interest level is rated Middle Grades (4–8), meaning the themes and content are designed for ages 9–14 (4th–8th grade). Themes include mystery-solving, brotherhood and teamwork, courage.

How long does it take to read The Secret of the Old Mill?

At a typical 5th grade reading pace, The Secret of the Old Mill takes around 4.3h to finish. The book has 43,000 words. Slower or faster readers may vary significantly.

Does The Secret of the Old Mill have an AR quiz?

Yes — The Secret of the Old Mill has an AR quiz available, worth 7 points. Your child will need to take and pass the quiz through their school's Accelerated Reader program to earn credit. The quiz is typically 5–20 multiple choice questions about plot, characters, and setting.

What grade level is The Secret of the Old Mill?

The Secret of the Old Mill has an AR reading level of 5.4, which places it at a 5th grade reading difficulty. The interest level is rated Middle Grades (4–8) — this reflects the age-appropriateness of the content and themes, not just the reading difficulty. A strong younger reader may handle the words fine while the themes are aimed at an older audience, or vice versa.