A convoy of circus trucks is passing through the ranch. The last truck in the column hits a bump and a large red box falls off and comes to rest in the pasture. Hank and Drover investigate the box and discover that it contains a circus monkey. Pete advises Hank not to open it, but Hank's curiosity gets the best of him. What follows is fun and adventure.

John R. Erickson, a former cowboy and ranch manager, is gifted with a storyteller's knack for spinning a yarn. Through the eyes of Hank the Cowdog, a smelly, smart-aleck Head of Ranch Security, Erickson gives readers a glimpse of daily life on a ranch in the West Texas Panhandle. This series of books and audios is in school libraries across the country, has sold more than 8 million copies, was a Book-of-the-Month Club selection, and has won an Audie for Outstanding Children's Series from the Audio Publisher's Association. Publishers Weekly called Hank a "grassroots publishing phenomena," and USA Today said this is "the best family entertainment in years."