In the Armenian Cathedral of St. John the Baptist in Paris, a Chilean refugee William Goetz, boys choir director and organist was assassinated. Kasdan, a retired police officer and parishioner of the cathedral, immediately began his own unofficial investigation. He is joined by Frank Salek from the Department for the Protection of Minors. It turns out that in the past a few boys disappeared from the choir which was directed by Goetz. The first criminality is followed by even bigger carnage. Between the investigation full of dangers into which heroes go and ancient chant "Miserere", there is a mysterious connection.