She is portrayed by Miranda Otto.
Prior to the events of Cocaine Blues, little is known of Lydia apart from the fact that she came from a familty who lost its wealth during the First World War, she was known for raising substantial ammounts of money for good causes (Prudence Stanley's hospital primarily noted). She is also shown to be outwardly devoted to her husband John.
Lydia was shown to be closely acquainted with Prudence and Phryne.
Lydia is introduced as the grieving widow of the recently deceased John Andrews. Prior to her husbands death, she had arranged a luncheon with Prudence Stanley and the recently returned Miss Phryne Fisher.
Shortly after greeting Phryne, she is seemingly overcome and taken ill. She is later questioned by Detective Jack Robinson and Constable Hugh Collin's but does not provide much information.
Phryne and Prudence host a charity evening that evening on her behalf (and Prudence's insistance) during which Phryne questions Lydia over a Maid who was recently sacked, Lydia responds that the maid was stealing and therefore was sent away without a reference.
Jack and Hugh return during the charity gala to reveal that Lydia's husband was poisoned with Arsenic in the sugar bowl, throwing suspicion on her remaining maid Dot who is taken for questioning, Lydia is shocked by this and later sacks Dot too after she is released.
Phryne later meets Lydia again at Madame Breyda's Bordello to discuss her husbands business dealings however Lydia states that she has no head for business and that she didn't want to discuss his life as they drink tea (refusing sugar in her own).
It is later revealed that Lydia herself was the one who murdered her husband by poisoning his breakfast tray when she appears after Phryne attempts to save Sasha from her goons. Proclaiming herself as the "King of Snow", she goes on to explain that after her family lost everything in the war and it was her intuition that saved her and John by building up her cocaine empire but her husband refused to let her have the money she earned, leading her to murder him and mildly poison herself to throw suspicion off her.
Lydia orders that Phryne and Sasha be stripped and left in the Sauna to die however due to the actions of Phryne's friends and companions, she is freed and informs Jack who is presumed to have arrested and charged Lydia for her crimes.