It's February, and Carnival time in Venice. Bright blue skies and freezing temperatures welcome Teresa Lupo, forensic pathologist to the Rome Questura, to the city. She is greeted off the vaporetto by an anonymous masked man dressed as The Plague Doctor. Teresa has taken time out from her job to find her beloved bohemian aunt Sofia who has mysteriously disappeared. There seem to be no clues as to her whereabouts, but a visit to Sofia's very strange apartment in the Dorsoduro confirms Teresa's suspicions that all is not well.