In Green Green Pastures, there exists a much loved legend about valiant dragon-slayers who lived in the Stone Age. Having grown up listening to stories about their awe-inspiring adventures, Pleasant Goat and Fatty Goat have always wanted to become dragon slayers themselves. While trying to make this dream come true, Fatty Goat inadvertently switches bodies with Big Big Wolf, and the two, along with Pleasant Goat, soon find themselves transported back to the Stone Age. When an evil dragon appears and threatens Stone Age Green Green Pastures, Fatty Goat, Big Big Wolf and Pleasant Goat must rise up to the dragon-slaying challenge.