While on tour in Barcelona, Grace is imprisoned for the theft of a rather spectacular work of art, a unique creation by the great Master Salvador himself.
Rushing to her aid, Fourmille and Yuri attempt to clear her name... All the while trying to get Sigisbert, who they brought along, tied up and gagged in their luggage, to confess the secret of the Preshauns! But whilst the spirit of a cat sometimes occupies that of Fourmille, the city worries about the numerous disappearances of young girls...