It proposes a fringe hypothesis regarding the relationship between Jesus, John the Baptist and Mary Magdalene, and states that their true story has been suppressed by the Roman Catholic Church through, among other tactics, the conscious selection of the texts that make up the canonical New Testament, their campaigns against heresy, and their propaganda against non-Christians.

Furthermore, they point out that their body angles form the letter M, a reference to the Magdalene, and that she and Jesus are dressed in similar but oppositely colored clothes, a negative image of each other.

They claim to find evidence for this occult tradition in such assorted subjects as The Knights Templar, the Cathars, Gnosticism, the Holy Grail, and the legends connected with southern France, and in particular the town of Rennes-le-Château.

Among their conclusions are the following: The authors offer, but not claim, that perhaps Leonardo da Vinci was sending veiled messages through his art, which could be understood only by others who were open to their meaning.

"[2] Writing for The Courier-Mail, Alison Coates similarly noted that "this is not a book for which serious academic claims can be made but it is not entirely without value, because it attempts (sometimes successfully) to put puzzling historical events into an understandable context and to raise important questions about the beginnings of the Christian church.