Doctor Gemma Foster is a woman in control. She's a talented and respected family doctor at the heart of her village - a woman people can trust and a loving mother. But Doctor Foster's life is about to explode. Suspecting her husband Simon of having an affair, she's determined to get to the truth - but how far is she prepared to go and what other betrayals might she uncover? As Gemma's investigation throws her life, and the lives of her patients and family, into chaos, she finds herself behaving in ways she could never have imagined. In trying to regain control, could she end up losing everything she loves?