After stealing a shipment of silver and weapons, the brutal and unstable Remy and his band of mercenaries must cross a river in order to flee into Mexico. Travis, the maverick owner-operator of a barge that ferries people and goods across the river, learns that Remy and his band are on the way. Travis and his woman, Nola, transport the nearby settlement's inhabitants and a group of passing settlers to the river's far side. When Remy and his band arrive, Travis refuses to cross back to pick them up, knowing that Remy and his men will kill everyone else after they cross the river. A tense standoff develops between Remy and his gang, and Travis and the inhabitants and settlers, who occupy opposite sides of the river. Remy is advised by Marquette, a Frenchman he trusts. Travis is greatly assisted by Mountain Phil, a friend of his who is similarly independent-minded in the way he lives. Both Remy and Travis have to contend with dissenters within their own camps. It all explodes into a violent and bloody battle, leading to a final confrontation between the two.