Bitz, Bob and Bevel are racing across the desert in a steam train to deliver ice cream for the opening of Purl's ice cream parlour. But rustlers Zippy the Kid and Prospector Pop want to get their paws on it and create a distraction before making off with the train's engine. Our heroes manage to get it back but there's no water left in the tank, which means there's no steam to make it go - and the ice cream is starting to melt in the heat. Will Purl's grand opening turn into a grand closing?