On October 16th 1969, a London auction house offered for sale a 13th century parchment containing a religious text scribed in Latin and pertaining to reference the legendary lost treasure of the Cathars. Following a graphology test, the writing was attributed to medieval Cathar historian, John of Lugio. In 1971, the new owner of the parchment, Gilbert de Cherisey, discovered a steganograph hidden behind the writing, containing references to the resting place of Christ - the Cross of Jerusalem, a Greek representation of Christ, and a Christogram. Following Gilbert's death, his son, James, continued the work his father had spent four decades attempting to prove. Leaving the confines of the de Cherisey baronial home of Weston Hall in Northamptonshire, James, accompanied by his childhood friend Amelie Rousseau, travels to Montsegur to decipher the clues hidden within the Lugio Parchment, and where, by chance, discovery of the keystone is made... The 9th Heresy will appeal to those who enjoy action and adventure books, that investigate historical and religious aspects.