Hemingway, yearning for adventure, volunteers for the Red Cross during World War I. He marries Hadley Richardson and moves to Paris, publishes The Sun Also Rises and finds critical and commercial success with his second novel, A Farewell to Arms.

Hemingway, having achieved a level of fame rarely seen in the literary world, settles in Key West with Pauline Pfeiffer but can't stay put for long. He reports on the Spanish Civil War and begins a tempestuous romance with Martha Gellhorn.

Hemingway follows the Army as they advance through Europe. Afterwards, he tries to start a life with Mary Welsh, but is beset with tragedies. He publishes The Old Man and the Sea to acclaim but is overcome by his declining mental condition.