Documentary revealing how Covid-19 spread unstoppably throughout the world, told through the eyes of key scientists on the pandemic frontline. Personal diaries recorded by scientists and intensive care doctors give an insight into the race to identify the virus and try to unlock the secrets of its virulence, revealing how scientists came to realise the seriousness of the disease. Racing to develop a vaccine, leading scientist Professor Sarah Gilbert discusses the pressures she faces and her hopes that a vaccine can be developed