Trapped at the Bottom of the Sea: The Cooper Kids Adventure Series Book 4 of 9 by Frank Peretti (1988)
Growing up, I never got into reading The Hardy Boys books—or any other serial adventure books, for that matter. Closest I ever got were the Choose Your Own Adventure books, which are short reads I still enjoy reading occasionally.
Unbeknownst to me in the 1980s, Frank Peretti—better known for his adult novels about spiritual warfare like This Present Darkness (1986) and The Visitation (1999)—was dishing out his own version of youth-focused adventure novels just like The Hardy Boys but with a spiritual bent that really brings faith to life.
Four years ago, I read Book 1 in this series, The Door in the Dragon’s Throat (1985) and found it a bit too demonically extreme for my kids (ages 9 and 11 at the time). This time, I read the book alone and definitely plan to pass it on to my kids. I have zero doctrinal qualms about this one, and the adventure is thick.
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Brief Summary of Trapped at the Bottom of the Sea
The story opens with an immediate mystery: two U.S. Airmen are conniving to hijack their own military plane. Enter 13-year-old Lile Cooper, an angry young girl who just wants to go home to Washington from Japan and leave her dad and brother far behind.
Despite this unexpected civilian passenger, the airmen continue with their plan to hijack the jet, a plan that quickly falls to pieces—as does the plane itself in the Pacific ocean.
The plane’s disappearance kicks Dr. Jacob Cooper and his son Jack into high gear as they race across the sea to help find young Lila. Along the way, they face guerillas, “commies”, and cannibals along the way.
What Makes These Books Move
Frank Peretti began this book in high gear, and he never let up. The action is constant, and the mystery remains strong throughout. I barely noticed myself zooming through 40 pages on a single bus ride across town.
I know my son (15) especially will enjoy this one, once he’s done with his current series. I only wish I had Books 2 and 3 (or the remaining books through #9) along with me as well!
A Little Lost with the Drama
One qualm I had with the book through the first few chapters was that I couldn’t figure out why Lila was so angry at her dad. It took Peretti until about 70% through the book to lay out again in lurid detail whatever we had missed by not reading Book 3. Lila and her dad had a falling out, because ever since the kids’ mother died, Dr. Cooper had refused to talk about her, as if he never loved her and never cared about anything but his work. And Lila was bold enough to say this to his face and to tell him that she wanted out.
Without an argument, her dad had acquiesced. He put her onto a plane, and now here she was sitting at the bottom of the ocean thinking that the last words she ever got to speak to her dad were words of anger and hate. I’ll let you read the book yourself to find out how she survives down there at the bottom of the sea, but just know that she has some real heart-to-hearts with God—a lot like Jonah before her.
Conclusion
Along with all the adventure, this book also contains a good deal of humor—unforced but definitely intentional—that makes for just some straight-up fun and edifying reading. In fact, it makes me want to go back and look up the books I missed and to continue on with Books 5-9.
I recall loving the Global Air Troubleshooters series by Jerry B. Jenkins for similar reasons—high adventure, fast-paced action, and edifying lessons for youth from a Christian perspective—and now I’ll say that Peretti’s books here are a close second in this little genre.
Check them out if you can find them and recommend them to your kids and grandkids. I don’t think you’ll be disappointed.
©2026 E.T.
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