The zoo stinks, and all fingers are pointed at tapirs Terry and Penelope, who are prone to plopping in their pool. Carlos the capybara shares their enclosure and is in a constant state of fury at their unhygienic ways. It soon becomes clear, however, that it's not just the tapirs causing the stink. All the zoo's residents need to scrub up. But can they clean up and stem the stench before the all-important arrival of the public?