The wheelie society is in conflict with Fenella the Kettle Witch, who speaks in a very strong Welsh accent and lives in Wheelie World but separately from the wheelies, in Spout Hall, an oversized kettle. Fenella hates happiness and uses her powers primarily to make the wheelies unhappy.
She has magical capabilities, including a form of teleportation which is her main mode of transport, and enchanted assistants including a magic book (called ‘Claptrap Von Spilldebeans’) and O’Reilly the Telescope, which advise her on magic spells.
Minions include spikers (sinister-looking objects like conker shells with baleful eyes, which roll everywhere) and toadies (pointed toadstools with similar eyes, which travel by bobbing through the ground as though it were water and who speak with a Chinese accent).
The wheelies have adopted into their society a “happiness dragon”, Chorlton, who appears in Wheelie World at the very beginning of the series, hatching out of an egg.
Chorlton is perpetually good-natured and perpetually clueless. For example, he fails to perceive Fenella as a villain, and affectionately refers to her as a “little old lady”.
Nevertheless, his presence negates the unhappiness magic, so the wheelies treat him as a hero. Despite being “Made in Chorlton-cum-Hardy” (Greater Manchester) he has a strong Yorkshire accent, although this is probably due to the voice talents of Joe Lynch more than any planning by Cosgrove Hall.
Plots are extremely simple, mainly revolve around Fenella’s schemes to make the wheelies unhappy and Chorlton’s accidental rectification of everything that goes wrong. Around these events, the characters’ simple and exaggerated personalities are on show.