For many years the Duke and his loyal knights have been fighting dragons, rescuing damsels in distress, and trying to make their dukedom safe for its people. Now they've finally succeeded: the last dragons in the realm have been killed. The Duke and most of his knights are happy to sit back and enjoy the peace they've made; but Sir Oblong fitz Oblong believes it's their duty to continue their good work in the desolate wastelands of the North. And their charter requires this decision must be unanimous.
The Duke's sidekick comes up with a solution: Have Sir Oblong appointed as a Knight Errant, and sent to pacify the nearby Bolligrew Island. Once he's away, the vote can be rerun, and without Sir Oblong the result will be unanimous.
Shortly afterwards, Sir Oblong arrives on the island with a list of tasks:
- Rebuild the Church.
- Restore justice to the Magistrates' Court.
- Suppress the island's dragon.
The island's current ruler, the eponymous Baron, isn't going to make things easy for him...
This play makes use of the following tropes:
- Anachronism Stew: Done deliberately. The knights, villagers and dragon are from a world of mediaeval fantasy; Bolligrew is a stock Wicked Baron from Victorian melodrama. Other elements, such as chocolate money and 'Colonel Bogey' are even more recent.
- Aristocrats Are Evil: As one might expect from the description of that trope, the Duke is kindly, if lazy, while Baron Bolligrew is a miserly cheat.
- The Darkness Gazes Back: The Dragon is represented by two glowing eyes in the entrance to its lair.
- The Dragon: The Baron's dim, thuggish enforcer, Squire Blackheart. There's also a literal dragon, of course.
- Familiar: Doctor Moloch has a magpie familiar, Mazeppa.
- Hypno Trinket: Moloch's spell "Grimbleboots" transforms a person's most prized possession into one of these. As long as they are wearing or carrying the object, they are in the power of the person whom the caster designates. When Moloch himself casts the spell, he adds an additional refinement: the controlled person doesn't even realise they're controlled.
- Names to Run Away from Really Fast: Squire Blackheart, Doctor Moloch.
- Our Dragons Are Different: Dragons in this setting die of 'mulligrubs' if their tails are cut off. They come in a range of colours; the Bolligrew Island dragon is black, with red eyes.
- Petting Zoo People: A necessity, given that the magpies are played by people.
- Repetitive Name: Sir Oblong Fitz Oblong, and the Duke's sidekick Sir Percival Smoothly Smoothe.
- Rewarded as a Traitor Deserves: Bolligrew tries to trick Doctor Moloch by paying him with chocolate money. Moloch promptly betrays their plan to the Dragon. The Dragon promises that Moloch will be well paid for that information, lures him into his cave to collect the money, and eats him.
- Species Surname: Mike's surname is Magpie.
- Thieving Magpie: Mike can't resist stealing shiny objects.
- Throwing Down the Gauntlet: Blackheart attempts to challenge Oblong to a duel using this, though Bolligrew has to coach him in the proper language to use (and Blackheart has to keep referring to his notes as he does it). Oblong refuses his challenge, but later issues one of his own once he's convinced of the Squire's villainy.
- Victory Is Boring: The Duke and his knights soon become tired of their peaceful, prosperous kingdom, and begin to envy Oblong's quest.
- The Voice: The dragon never appears on stage — all that can be seen are its glowing eyes.
Robert Bolt's novelisation makes use of the following additional tropes:
- Adaptation Species Change: The play's magpies are replaced by hobgoblins. This also includes a Gender Flip (Mike becomes the female hobgoblin Jackie) and an Adaptation Name Change (Mazeppa becomes Tiberius).
- Named by the Adaptation: The Duke is named as Alonso, and Squire Blackheart gets the forename Joseph.
- Promotion To Love Interest: A romance between the hobgoblins is added.
- Worthless Yellow Rocks: When luring Moloch into the cave, the dragon pretends not to see any value in its pile of gold coins. "I can't think what people make of them out there. They're quite inedible."