When fourteen-year-old Theo falls into a mysterious malaise, his aunt Martha whisks him away on a global tour to seek a cure through the exploration of the world's diverse religious traditions. Theo, a clever and skeptical Parisian teenager, finds his worldview challenged as he encounters various faiths and cultural practices across the globe. His parents' decision to withhold religious education leaves him as a blank slate, forcing him to navigate these complex spiritual landscapes with a critical, analytical mind. The narrative unfolds as a series of encounters, blending the intimacy of a personal quest with the intellectual rigor of a comparative study.

This work is frequently compared to Jostein Gaarder's Sophie's World for its ability to distill complex theological concepts into an accessible narrative format. Readers often highlight the author's success in maintaining a balanced, non-dogmatic perspective that respects the diversity of human belief systems. The protagonist's skeptical nature serves as a useful proxy for the reader, allowing for a grounded exploration of abstract spiritual questions. The prose is noted for its wit and clarity, ensuring that the heavy subject matter remains engaging throughout the global tour. The book functions as a thoughtful primer for those interested in the historical and cultural foundations of religion.