Protagonist Dr Gemma Foster goes down a dark path in this mystery drama series. A trusted GP with many friends and a settled family, Dr Foster seemed to have the perfect life. That is, until her property developer husband, Simon, starts acting suspiciously and she thinks he is having an affair. Gemma uncovers secrets that tear her world apart, with her family and patients all suffering as a result. Her perfect life is thrown into turmoil as she discovers that both her and Simon's actions have long-reaching consequences.