Readers of this exciting action series are already well acquainted with the Pony Rider Boys to need a formal introduction. As told in "The Pony Rider Boys in the Rockies," the lads had set out from their homes in Missouri for a summer's vacation in the saddle. The first volume detailed how they hunted big game and how they finally discovered the Lost Claim, which they won after fighting a battle with the mountaineers, thus earning for themselves quite a fortune.