First of a two-part documentary in which four famous faces get first-hand experience of working at King's College Hospital, London. Medical journalist Michael Mosley joins the resuscitation team in A&E, bringing back vivid memories of his doctor training back in the early 1980s, while journalist Stacey Dooley joins the Heart Attack Centre - the first in the country to treat attacks while they are taking place. Ex-politician Ann Widdecombe works alongside the nurses in the Urgent Care unit, and Paralympic athlete Jonnie Peacock, who lost a leg to meningitis at the age of five, spends time on the children's wards and in theatre support.