Filth is Witch Sludgegooey's Fiend, Arthur the Dragon is precise, meticulous and lives with his mum, and O'Brian is a Leprechaun who is often mistaken for a Pixie. These three very different characters have two things in common – the band they play in (The Witchway Rhythm Boys) and the music they play – Crash 'n' Bang– which nobody likes very much. But then The Thing in the Moonmad T-shirt becomes their manager and sets their sights higher – on the forthcoming music competition The Battle of the Bands, where they face stiff opposition from some terrifying Skeletons, Trolls and Gnomes.