Farmyard Flyers

Farmer Jolly is a very attentive farmer. All his animals are exceptionally well cared for. Pig, in particular, is thoroughly spoilt, and spends most of his time lounging around with a glass of lemonade in one hoof, and an aviation magazine in the other (he's crazy about planes.) But suddenly Farmer Jolly seems distracted and things don't seem to be running quite so smoothly as before. Then the animals start hearing noises at night from the barn. Bang, bang, bang. Clunk, clunk, clunk. One thing is clear - Farmer Jolly is Up to Something. But what?