"It's brill! It's catchy! It makes your feet itch!" That's what all the young farm animals think of the whistling of Henry, the world's first whistling piglet, and whenever he whistled one tune similar to "The greenwood tree", they would all jump up and follow him. All the adult animals complain as well as the farmer who decides to send him to market. But, instead of getting into the farm truck, Henry starts whistling that tune and runs away to the greenwood with all the young animals following. Though it takes the farm workers a long time to collect all the animals back again, they never do find Henry. And the sound of that whistling is heard -- now and again -- coming from the greenwood.