Bret, seeking buried Confederate treasure in Elwood, Kansas, keeps running afoul of U.S. Marshal Mort Dooley. The marshal keeps running Bret out of town. Bret, in turn, keeps outwitting the lawman.

Bret is one of the seven owners of a Riverboat who start down the Mississippi for Memphis to sell the broken-down craft, but soon in a deadly game of 10 Little Indians one owner after another is found mysteriously dead. It becomes apparent that if the boat does reach Memphis, it's almost certain it will have but one owner.