Reviewed by HootRated editorial · Last updated
Horizon
Jenn Reese
Horizon
Age Rating, Reading Level & Content Guide
Above World #3
by Jenn Reese
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.
We may earn a commission from these links. Bookshop.org supports independent bookstores with every purchase.
About This Book
The salty spray of the sea stings Aluna’s face as she and her friends dive into the depths of the underwater city. The echo of clashing metal and whirring machines fills the water around them, a sign that danger is closer than ever. Together, they must face a terrifying enemy and decide if their friendship is strong enough to save their world.
Themes
Quick Assessment
Horizon is the thrilling conclusion to the Above World series, featuring a group of young friends from diverse backgrounds who embark on a daring mission to prevent a war. Suitable for ages 9 to 12, this middle-grade fantasy explores themes of friendship, loyalty, and courage against a backdrop of underwater cities and technological threats. Parents should note the presence of conflict and peril but find the story ultimately uplifting and adventurous.
Why we rated Horizon 9ME
Horizon is written at a Level 4-5 reading level with a Lexile measure of 750L across 390 pages. Strong independent readers around grade 5.5 can typically handle this book on their own; with parent or teacher support, Horizon works for readers up to grade 6.5.
We rate Horizon as 9ME ("Moderate — Emotional") because the content sits in the "Moderate" range — moderate conflict that may involve loss, scary scenes, or interpersonal stakes. The strongest signals come from emotional weight, 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, Horizon explores adventure, friendship, fantasy world-building, quest, and dystopia — 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.
- ✓ Patient readers who enjoy slower, character-driven stories.
- ✓ Kids drawn to stories about adventure, friendship, fantasy world-building.
Maybe not for
- ! Readers who get easily upset by emotional or moderately dark scenes — the conflict here is real, not just background flavor.
- ! Reluctant readers who need a fast hook — the pacing here rewards patience.
For Parents
Content Intensity
9ME — Moderate — EmotionalReal stakes and emotional weight. May include sustained danger, loss, or bullying.
Was our "Moderate" content intensity rating accurate for this book?
Reading Insights
Hook Factor
2/10A steady, thoughtful read that rewards patient readers.
Discussion Potential
2/10A lighter read — great for independent enjoyment.
Book DNA
Multi-dimensional content fingerprint
Similar Books
Based on content and theme analysis
Above World
Jenn Reese
Above World
Jenn Reese
Oceanborn
Amalie Howard
Oceanborn
Amalie Howard
Jemma and the Mermaid's Call
Laura VonDracek
Jemma and the Mermaid's Call
Laura VonDracek
Sunset Sea
Breanna Maples
Sunset Sea
Breanna Maples
Danger in the Deep Blue Sea
Debbie Dadey
Danger in the Deep Blue Sea
Debbie Dadey
Under the Sea
Kyla Steinkraus
Under the Sea
Kyla Steinkraus
Details
Book Length
- ISBN
- 9780763664176
- Pages
- 390
- Publisher
- National Geographic Books
- Published
- 2014
- Type
- Fiction
- Lexile
- 750L