As we emerge from a global pandemic that has turned our world upside down, David Olusoga explores the hidden history of the nurses, doctors and health workers who, for more than 70 years, have been coming to Britain from overseas to serve in the NHS. Without them the NHS would have been in danger of collapse - not least during the current COVID crisis - but from the very start the story of this beloved British institution has been intertwined with one of the most divisive social and political issue of the age, immigration. The people who came to this country to work in the NHS have found themselves fighting battles they neither sought nor expected.