American translator Cassandra Reilly has lived for some time in Barcelona. One day another American woman turns up, Frankie Stevens, very strikingly dressed and made up as a ‘femme fatal.’ She tries to convince Cassandra to help her find her husband who has mysteriously become lost in Gaudí’s city. At first Cassandra refuses, but then lured by the large sum promised for help, she is persuaded to change her mind. Because she often translates detective novels she has an idea where to start looking. She soon finds out that not everything is as Frankie has told her. After meeting the sensual April and the mysterious Bernadette she gets more deeply caught in a web of strange coincidences and mistaken identities. When in the end Cassandra solves the family mystery, a riddle more complicated than Gaudí’s intriguing architecture, she is finally ready to begin solving the puzzle of her own past.