The railhead town of McCoy is busy, far busier than it has been for many seasons. Gene Adams and his riders of the Bar 10 are delayed and find their herd of prime longhorn steers arriving after two other herds of steers have filled the stock pens. It proves costly to Adams – the Circle O and the Lazy J herds have taken the bulk of the cattle agent’s cash and left little for his beeves.
As the Bar 10 boys go to bed in their downtown hotel, they are unaware of what is occurring in the plushest part of town. Corrupt cattle agent Roscoe Martin has hired the infamous gunfighter Chance Taylor to rob the weary Circle O and Lazy J boys of their money as they make their way home. When it comes to light, Gene Adams and his cowboys must saddle up in a bid to warn their rivals. They are no longer just cowboys: they are the Knights of the Bar 10.