In 1937, 28-year-old Martha Gellhorn travels alone to Madrid to report on the atrocities of the Spanish Civil War and becomes drawn to the stories of ordinary people caught in the devastating conflict. It's her chance to prove herself a worthy journalist in a field dominated by men. There she also finds herself unexpectedly - and unwillingly - falling in love with Ernest Hemingway, a man on his way to becoming a legend.
On the eve of World War II, and set against the turbulent backdrops of Madrid and Cuba, Martha and Ernest's relationship and careers ignite. But when Ernest publishes the biggest literary success of his career, For Whom the Bell Tolls, they are no longer equals, and Martha must forge a path as her own woman and writer.