During the First World War, Frederic Henry, a young American, drives ambulances for the Italian army on the mountain front. There he meets Catherine Barkley, an English nurse. Wounded, he is treated in a hospital in Milan, and their affair becomes a great love.
Hemingway had himself driven ambulances on that front, been wounded and loved a nurse. He tells of war without heroics, and of a love that tries to escape the war.
Its short, simple sentences and plentiful dialogue make it easy to read in the language you are learning.
