The residents of Mossy Bottom Farm looking forward to Halloween – until the clumsy Farmer trashes the flock’s beloved pumpkin patch! When Shaun turns mad scientist to fix the problem, things rapidly spiral out of control. With the Farmer missing and a wild beast roaming the woods of Mossingham, all the ingredients are in place for a monstrously fun family adventure.

故事继续围绕小羊肖恩展开，当农场遭到突袭，羊群们被套上厚厚的长袜，小羊羔Timmy却因此突然失踪。