'Vege-mania' is sweeping Wallace and Gromit's neighborhood, so the two enterprising chums are cashing in with their company, "Anti-Pesto." Business is booming, and only days remain before the annual Giant Vegetable Competition. Suddenly, a huge, mysterious, veg-ravaging "beast" begins attacking the town's vegetable plots at night, and the competition hostess, Lady Companula Tottington, commissions Anti-Pesto to catch it and save the day.