Enrique Alonso, writer, receives a letter from his adoptive father, Artur Aiguader, one of the most famous antique dealers in Barcelona, in which he recounts the discovery of an ancient manuscript written in Latin and ancient Catalan that seems to put him on the track of a jewel of a remote past. Unfortunately, Artur will not see his dream fulfilled to find it, he will be killed. Henry moved to Barcelona in order to find the explanation to the mysteries of the manuscript, to solve the murder and try to find this gem for which his father apparently died.