The pirate captain Longhorn Silver and his band of buccaneers have been robbing trains and causing trouble on Moo Mesa's waterways. With a gold shipment and Cody's money for new boots in their possession, Moo Montana, Dakota Dude, and Cowlorado Kid have to go to Newportleans to track these pirates down. While trying to get back the money, Cody is caught by the Masked Bull as part of his plan to work with Longhorn Silver to dispose of the C.O.W.-Boys. Now the C.O.W.-Boys must rescue Cody, reclaim the stolen loot, and defeat Longhorn Silver.