Cyrus and Rudy have found the perfect way to spend the last days of summer: a roadside stand where they sell their dahlias, blackberries and tomatoes to the passing motorists. When a neighbor drops off a bin full of red wrigglers, California earthworms that break down compost into fertilizer, Rudy and Cyrus become worm moguls as they discover just how in demand the Eisenia fetida are. Especially as the local agricultural fair approaches, an event that teaches Cyrus an important lesson in honesty. Black Gold is the third book featuring Cyrus and Rudy's adventures on the farm, following Blackberry Juice and Not for Sale .