Two years after Doctor Gemma Foster dramatically exposed her husband Simon's betrayals, forcing him to leave town, her life is destabilised once again when he returns.

Reeling from the repercussions of Simon's return, Gemma scrambles to uncover his secrets and find out what's going on with Tom.

Gemma feels Tom should come first, even though she and Simon are at each other's throats. But can they put their own feelings aside for their son's sake?

Simon feels confident that he and Kate can finally live securely, free from Gemma's shadow. But can Kate really trust him?

Gemma goes to extreme lengths in order to come out on top and win back her old life. But this time has she gone too far?