The prelude is set in 1919 on Eddington's expedition in Príncipe to observe the solar eclipse that year, before moving back in time to 1914. At the outbreak of the First World War, Eddington is appointed chief astronomer at Cambridge by Sir Oliver Lodge and instructed to research Einstein's work and defend the Newtonian status quo. Meanwhile, Einstein is lured back from Zurich to the Prussian Academy of Sciences in Berlin in an attempt to aid the war effort by embarrassing Britain by disproving the work of its great scientist Isaac Newton. In Berlin, with his marriage already under tension, Einstein falls in love with his cousin Elsa.