Constance Isles is the adoptive mother of Maura Isles.
She introduced in the season 2 episode Rebel Without a Pause where she visits Maura in Boston. Maura starts to hyperventilate when her mother comes to Boston a day earlier than planned. She mentions that she has to prepare a 11 course meal for her mother but she does not have to time to do so because of the on going case. She then decides to order take out. This makes her nervous because she thinks her mother will discover that she has not prepared the meal herself. The dinner party goes pleasantly until Constance informs Maura that she will not be staying at her house and has instead checked in at The Ritz which upsets Maura. She invited Maura to a dinner party and promises to meet up with her the next day. However, the next day, she calls Maura and tells her that she is not allowed to bring a guest to the dinner party. Jane is astonished because Maura is her daughter and not merely a guest. The next day, Maura dresses up for her mother's art installation and invites Jane to go. When they get there, it is revelaed the Constance has forgotten to put Maura on the guest list. Jane shows her police badge and gains entry with Maura. At the art exhibit Jane confronts Constance, telling her that she is hurting Maura by not showing any affection towards her. Constance defends herself, saying that she knows Maura is busy and she doesn't want to intrude on her life but that she is very proud of Maura. Jane tells her that she should tell Maura that. Later she joins Jane, Maura and Angela at The Dirty Robber where she orders milkshake because she hasn't had one in years.
In Season 2 finale, Burning Down the House she is a victim of the hit and run case relating to the case Maura was working on. She and Maura we're walking home after dinner when a car came towards them. She pushed Maura out of the way but was hit by the car and severely injured. She was then taken to the hospital where she underwent surgery to save her life. At the end of the episode she is shown to be critical but stable.