In the opening to City of Masks, Giuliana is revealed to be the woman who had taken the place of the Duchessa during the Marriage with the Sea rite. In exchange for her services as a body-double, Giuliana was paid a large amount of silver and agreed that she would never reveal that she had been the Duchessa's double or otherwise be immediately exiled from Bellezza.
Giuliana returns to her fiance, intending to use the silver for her wedding and as part of her dowry. However, Enrico pressures Giuliana to reveal how she obtained the silver and she admits to Enrico and Rinaldo di Chimici that she had taken the Duchessa's place during the Marriage with the Sea that year.
Though Giuliana comes to suspect that Enrico's activities are unsavory and possibly treasonous, she immerses herself in planning her upcoming wedding and arranges for a dress to be made by a lacemaker, Paola Bellini. Paola relays to Silvia that Rinaldo intends to attack her in the Glass Room during one of Silvia's sessions, revealing to Silvia that Giuliana had broken their agreement.
As a result, Silvia requests that Giuliana act as her body double again, this time just sitting listening to the people's requests, despite the fact Silvia rarely used the same woman twice as her double. Giuliana eagerly accepts as her love of silver had begun to eclipse even her love of Enrico. During the session in the Glass Room, Enrico arrives with a bomb to destroy the Glass Room. Giuliana is killed and buried as the Duchessa.
Giuliana's death becomes a lingering mystery for Enrico when he learns that she has disappeared after he is confronted by her father, Vittorio Massi. While he concludes that she must have run away with another man, he remains suspicious as she had not taken any of her belongings or any silver. He realizes that he accidentally killed Giuliana in the place of Silvia during the duel between Luciano Crinamorte and Niccolo di Chimici when Rinaldo recognizes one of the duel's spectators is the former supposedly dead Duchessa of Bellezza. Enraged that the di Chimici were the reason behind causing Giuliana's death, Enrico betrays them and offers his services to Luciano. Vittorio later learns of his daughter's death when Silvia publicly reveals that she is still alive and Arianna Rossi, the new Duchessa, privately discloses to Vittorio that Giuliana had died in Silvia's place during the explosion in the Glass Room when Paola Bellini, the Duchessa's grandmother, brings the silver that Giuliana had left behind. Vittorio, blaming the di Chimici for his daughter's needless death, dies after killing Rinaldo di Chimici on the day of the Duchessa's wedding to Luciano Crinamorte.