Detective Thomas and the Mysteriously Perfect Plan

Stephanie Quesnelle and her 7-year-old daughter teamed up to review the second book in Caitlin Bootsma's mystery series for readers of chapter books.

Detective Thomas and the Mysteriously Perfect Plan 

By Caitlin Bootsma

Published by OSV Kids

In Detective Thomas and the Mysteriously Perfect Plan, Caitlin Bootsma takes children on an incredible adventure through Marian dogma and apparitions, all to help Detective Thomas figure out why Mary matters so much to Catholics. The most interesting part is it’s positioned as a response to Protestant questioning, which helps kids understand, in a tangible way, what makes Catholicism distinct.

The best part about the Detective Thomas series (and the first book in the series is also amazing!) is that there are multiple open-ended questions for the kids to ponder or talk about with you. So while Thomas starts with the question “the Mystery of Mary. Why do we care so much?” readers are invited to ponder big and little questions such as: Can you think of other titles of Mary?

Clear, Accessible Foundation for a Child's Relationship with the Mother of God

The process that Detective Thomas goes through to understand Mary brings children along in an accessible manner. It doesn’t tell them who Mary is and why she is important, Caitlin clearly shows through the clues and critical thinking process how Detective Thomas figures it all out. The argument is meticulously laid out and brings readers to their own deeper understanding of Mariology, explained in kid-friendly terms with real events like the Council of Ephesus.

More importantly, Detective Thomas and the Mysteriously Perfect Plan introduces kids to the real ways Mary is present to us today. It lays foundations for a relationship with Mary as the Mother of God. Detective Thomas prays often throughout the book, demonstrating for readers prayer in action, not just a Hail Mary, but heartfelt words.

One of my favorite aspects of the whole book is the mystery structure and need to dig deep. Detective Thomas is quick to discover answers to clues, but sometimes figuring out why that clue matters requires further thinking. He isn’t using Google or smartphones for the answers, but learning through relationships, books, and other tools along the way, which highlights the communal nature of learning and models for kids exactly how to find a good answer.

The secondary mystery of the identity of the saintly helper KW was another fun aspect of the book.

Spoiler alert!

As a long-time devotee of Saint John Paul II, I love that Karol Wojtyla is the kids’ guide through this mystery. He had a beautiful devotion to Mary after his mother’s death and is the perfect saint to help kids learn about Mary. The kids learn about his motto, Totus Tuus, or “totally yours” while visiting a small museum about his life.

This book is the perfect read for middle-upper elementary school kids, especially ones with big questions.

Bonus Review from Esther, 7 years old

A kid that doesn’t know a lot about the Immaculate Conception would learn a lot in this book. This book’s genre is mystery. The detective’s name is Thomas, he is Catholic. Thomas’s cousin’s name is Hope, she is Protestant. Thomas tries to solve a mystery about Mary, he calls it: The Mystery of Mary.

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Copyright 2026 Stephanie Quesnelle
Images: (center) copyright 2026 Stephanie Quesnelle, all rights reserved.
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