After surrendering Fort Holman to the Confederacy without there being a single shot fired, Col. Pembroke (James Coburn) faces public disgrace and a potential court-martial unless he's able to recapture the fort now held by the power-mad Maj. Ward (Telly Savalas). To help him on this mission, Pembroke enlists a ragtag bunch of condemned men who are promised their freedom should they survive. Despite much internal strife, the group gradually comes together in time for the assault.