Faeries.

While waiting for their new home to be renovated, Nellie and her younger brother George are sent to a farm in the countryside, much to George's delight and Nellie's disgust. However, the farmhouse and the surrounding area are teeming with fey creatures. The first the two children encounter is a somewhat crotchety and unfriendly hobgoblin named Broom, who is (more or less) secretly looking after the farm.