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Line of Fire

Franklin W. Dixon

Cover of Line of Fire

Line of Fire

Age Rating, Reading Level & Content Guide

The Hardy Boys Casefiles #16

by Franklin W. Dixon

Reading Level 4-5 9MP Ages 9-12 Matched

The text is written at a 4th grade reading level, the subject matter is intended for middle graders (ages 9–12), and the content has moderate intensity with some emotionally heavy themes.

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About This Book

Smoke curls thick and sharp as Frank and Joe race through the blazing chemical plant, searching for clues that could prove Denny’s father was no accident. Flames crackle around them while secrets hide in every shadow. Just when they think they’re close to the truth, a sudden explosion stops them in their tracks.

Quick Assessment

This middle-grade mystery follows Frank and Joe Hardy as they help their friend Denny uncover the truth behind a suspicious fire at a chemical plant that may have been a cover-up for foul play. The story contains themes of espionage and detective work appropriate for ages 9 to 12, with moderate suspense and some perilous situations. Parents should be aware of scenes involving fire and danger but will find the content suitable for young readers interested in mysteries.

Why we rated Line of Fire 9MP

Line of Fire is written at a Level 4-5 reading level across 160 pages. Strong independent readers around grade 5.5 can typically handle this book on their own; with parent or teacher support, Line of Fire works for readers up to grade 6.5.

We rate Line of Fire as 9MP ("Moderate — Physical") because the content sits in the "Moderate" range — moderate conflict that may involve loss, scary scenes, or interpersonal stakes. The strongest signals come from physical peril — these are the dimensions parents should evaluate against their reader's tolerance.

No specific content flags were raised by community reviewers, which is consistent with the moderate intensity score.

Thematically, Line of Fire explores mystery, adventure, and friendship — these threads give the book room to mean different things to different readers.

Good fit for

  • Children in the Ages 9-12 range — the maturity and attention span match the story's pacing.
  • Kids drawn to stories about mystery, adventure, friendship.

Maybe not for

  • ! Readers who get easily upset by emotional or moderately dark scenes — the conflict here is real, not just background flavor.

For Parents

Content Intensity

9MP — Moderate — Physical
Emotional
Light
Physical
Moderate
Social
Clear
Thematic
Light

Real stakes and emotional weight. May include sustained danger, loss, or bullying.

Data confidence: standard

Was our "Moderate" content intensity rating accurate for this book?

Reading Insights

Hook Factor

3/10

A steady, thoughtful read that rewards patient readers.

Discussion Potential

2/10

A lighter read — great for independent enjoyment.

Book DNA

Multi-dimensional content fingerprint

Vocabulary Level
4
Emotional Weight
6
Theme Richness
3
World Scope
1
Data Confidence
7

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Details

Book Length

160 pages
ISBN
9780671688059
Pages
160
Publisher
Pocket Books
Published
May 15, 1989
Type
Fiction

Genres

Subjects

Mysteries, Espionage, & Detective StoriesMysteryMystery and Detective StoriesHardy Boys