Medical Defence Australia, a team of lawyers and doctors who defend doctors charged with malpractice, ranging from Botox injections gone wrong to spinal cord injuries.

MDA is an Australian Medical Defense Organisation. It serves an insurance function, defending the doctors who form its membership against lawsuits and malpractice actions, in return for a fixed annual fee. Its staff are a mixture of lawyers and doctors, led by lawyer Bill 'Happy' Henderson (Shane Bourne). He is ably aided by Dr Ella Davies (Kerry Amstrong), who later leaves to become head of emergency medicine at nearby St Albans hospital. Jason Donovan plays nemesis Richard Savage, a partner at Kato and Pittman, seen either as a wily and passionate advocate for patient rights, or an ambulance-chaser.

Enter the world of Medical Defence Australia, a medico-legal organisation that exists to defend doctors and where necessary compensate patients. All cases at MDA combine elements of law and medicine so each case is managed by a doctor and a lawyer who agree on how to proceed. It's a unique organisation that delves into morally complex and emotion filled relationships between doctors and patients.