One Life tells the true story of Sir Nicholas "Nicky" Winton, a young London broker, played by Johnny Flynn, who rescues over six-hundred children from the Nazis in the months leading up to the Second World War. After discovering families who fled the rise of the Nazis, he immediately realises it's a race against time. How many children can he rescue before the borders close? Fifty years later, it's 1988 and Nicky, played by Anthony Hopkins, lives haunted by the fate of the children he wasn't able to bring to safety. It's not until a live BBC television show That's Life! surprises him by introducing him to some survivors - now adults - that he can begin to come to terms with the guilt and grief he has carried for five decades.