Chilean refugee Wilhelm Goetz, director of the boys' choir and organist, was killed in the Armenian Cathedral of St. John the Baptist in Paris. Kasdan, a retired police officer and cathedral parishioner, immediately begins his own informal investigation. He is joined by Volokin from the department for the protection of the rights of minors. It turns out that several boys from the choirs led by Goetz have disappeared in the past. The first crime is followed by even bloodier murders. There is a mysterious connection between the dangerous investigation that the heroes embark on and the ancient chorale “Miserere”...