A flock of sheep graze on the edge of a peaceful French forest. But these are not your average sheep and, in reality, the setting is far from tranquil. While the herd are the cleverest you will ever encounter, thanks to their shepherds' regular bedtime stories and previous testing of their detective skills, they are unprepared for a fresh threat.

Several sheep have recently disappeared, and other creatures have fallen prey to a shadowy figure. The theory of a werewolf might be just a wild fairy tale, but when a human is killed, it becomes clear that even fantasies can be fatal. Miss Maple, Mopple and the rest of the flock, with the help of their goat neighbours, follow the werewolf's trail in a desperate attempt to stop the killings with sheep logic, courage, and concentrated food.