Dave Carr a young worker and dedicated communist decides to join joins an international group of freedom fighters in order to wage the good war against fascism in 1936.
On the train he mets Frenchman Bernard who presents him to a militia of left socialist workers in Barcelona. The men have only old rifles, but are highly motivated. Here David meets Blanca whose husband was killed when their besieged village was liberated.
The militia is peployed to the Aragon front. During a training excercise David is severly wounded by an old rifle. The American Gene Lawrence blames their comrades for the accident because they refused to support the Stalin-backed peoples army that supplied with modern guns.
After he leaves the hospital David meets Blanca in Barcelona again, whilst the fight between leftist socialist and communist escalates. Their love-affair comes to an abrupt end when David decides to join the communists.
The experience proves far less heroic than expected, however, as the fighters struggle with poor supplies, a lack of training, and internal discord. The traditional battles and romances of war drama follow, as Carr becomes involved in a tumultuous affair with a fellow fighter.