Susan and John are excited when they learn that F R Peregrine's Travelling Fair is coming to Scatterbrook, and Worzel recalls the legend of a fairground organ that an send humans to sleep.

Susan and John are excited when they learn that F R Peregrine's Travelling Fair is coming to Scatterbrook for one night only. But as much as he'd love to join his friends, Worzel can't be seen wandering around by humans. He recalls the legend of a fairground with an enchanted organ. It's believed that, with the right music, the organ has the power to send humans to sleep so that scarecrows can enjoy the rides without the fear of being seen.

At the museum, Aunt Sally finds herself agreeing to go on an adventure with another ex-fairground attraction, Calliope Jane, and it turns out Worzel isn't the only scarecrow who wants to attend the fair...

As the scarecrows descend the risk of being seen intensifies, but will the legend of the enchanted organ turn out to be true?