In the Spring of 1914, with Europe on the brink of war, no one had heard of an obscure German physicist called Albert Einstein. A British astronomer, Arthur Eddington, realised that Einstein's theories could unlock whole new ways of thinking about time and space. Despite the danger of being labelled traitors, the two men began a unique correspondence. An eclipse in Africa provided an opportunity to prove Einstein's theories to the world. Eddington, an unlikely hero, set out on a journey that would change people's perceptions of the universe forever.