Renegade adventurer Alvarez Kelly (William Holden) gets caught in the middle of the Civil War. With no loyalties to either North or South, Kelly is hired to drive a herd of cattle from Mexico to the Union Army in Virginia. However, along the way he is captured by Confederate Colonel Tom Rossiter (Richard Widmark) who persuades him by shooting off a finger to deliver the cattle to starving Confederates in Richmond. At a bridge leading to Richmond, the Union Army attacks and a bloody battle ensues in which Kelly risks his own life to save a Confederate officer. In the end, Kelly's fate once again lies in the hands of Colonel Rossiter.