Some mysterious graffiti on the walls of the Castillet, a crowned reptile in Saint Jean Cathedral, the Campo Santo defiled: these are some of the bizarre clues in Lieutenant Dominique d'Astié's latest investigation.

Is there a link between their symbolism, the enigmatic poems strewn all over the streets of Perpignan and the bloody assassination of "King Arthur Pendragon"?

The young Parisian police officer, newest member of La Police Judiciaire de Perpignan, will need to brush up on the old Arthurian legends if she is to solve this very non-Catalan murder!