The Devil's Daughter by Danielle Steel

At just 19, cold-hearted Mickie moves to LA to become a ‘star’ and joins modelling agencies. Warm-hearted Billie, a clever scientist, graduates from MIT but is unable to get work and is persuaded by Mickie to join her in LA, where she gets a research job in a hospital. Mickie meets Addison, a skilled but unscrupulous cosmetic dermatologist, and Billie meets a young journalist. Mickie’s life is transformed as she becomes Addison’s poster girl, enjoying extreme wealth. Billie’s boyfriend is the journalist who exposes him as a fraud following a trial where he’s sent to jail after catastrophic results of his treatments are revealed. The dynamic of the sisters’ relationship is key to the story and as usual, Danielle’s storytelling skills weave a fascinating plot around their psyches and the people with whom they interact.