On a cold day, the fictional 304th New York Infantry Regiment awaits battle beside a river.

Eighteen-year-old Private Henry Fleming, remembering his romantic reasons for enlisting as well as his mother's resulting protests, wonders whether he will remain brave in the face of fear or turn and run.

He is comforted by one of his friends from home, Jim Conklin, who admits that he would run from battle if his fellow soldiers also fled.

During the regiment's first battle, Confederate soldiers charge, but are repelled.

The enemy quickly regroups and attacks again, this time forcing some of the unprepared Union soldiers to flee.

Fearing the battle is a lost cause, Henry deserts his regiment.

It is not until after he reaches the rear of the army that he overhears a general announcing the Union's victory.