Doctor Gemma Foster is a woman seemingly in control: a trusted GP, the heart of her town, a woman people can trust. But her life is about to explode. Suspecting her husband of having an affair, Gemma throws herself into an investigation that will propel her, her family, and even her patients into chaos. Bit by bit, Doctor Foster uncovers secrets that shock her to the core - and she is going to behave in ways she could never have imagined.