"Big John" is a 12-year-old boy living as a serf in 13th century England, but with a mysterious past understood only by "Old Marm", who has raised him as a son and teaches him lessons and courtly behavior in secret. He is finally recognized by a knight and learns that his father was betrayed long-ago by a fellow nobleman and his nurse rescued him along with a few precious family heirlooms. After training at a castle under this knight, he sets out on the 5th Crusade (starting in the year 1218 - he is now 16 years old) as a squire - largely in hopes of finding his lost father.

This is an interesting and engaging story for middle-school children - especially 5th to 8th grade. It offers a surprisingly balanced view of the Crusades as well as beautiful themes of faithfulness and forgiveness. While written at an appropriate level for young children, the author is honest about the evil and destruction that came out of the previous crusade (the infamous 4th crusade in which the Christians sacked Constantinople). In the course of discussion, the characters further distinguish between those who come to the Crusades to free Christian prisoners and those who are after glory and material gain. Finally, this subtle running theme about motive and warfare is brought to a climax in the person of St. Francis of Assisi.

While some of the plot comes across as a little predictable (making it less appealing, perhaps to high schoolers), the themes and major events are thoughtful and extremely well-researched. The segment in which Big John crosses paths with St. Francis of Assisi is based on a true incident in which the Saint went into the Saracen camp to preach to the Sultan about Christ.