Frederick Henry is a American architect serving for the Italian Army as an ambulance driver during World War I. During a bombarding raid he meets British nurse Catherine Barkley who serves for the Red Cross. A romance develops between the two fast, but the question is can it last in the midst of a terrible war. The two get separated when Henry gets sent to the front. They try to keep in touch but their correspondence is blocked by his jealous commanding officer. When Henry discovers Catherine is in Switzerland he deserts determined to find her.