It follows the adventures of the crew of the Paradox, led by Captain Thrice, on their quest to find the legendary Lavender Castle and prevent Big Bad Dr Agon from destroying it.
The crew of the Paradox include Captain Thrice, his walking stick which was brought to life during a previous encounter with Lavender Castle, Isambard (Engineer), Roger (Pilot), Lyca (Doctor), Sir Squeakalot (Ship's robot) and Sproggle (Navigator).
Lavender Castle provides examples of the following tropes:
- Binary Suns: The planet Bharron has these, which eclipse once every thousand years. During then, Lavender castle manifests in the planet's sky.
- Clip Show: The last episode of Series 1, Birds of a Feather, which has the villains recalling how they've tried and failed to defeat the Paradox.
- Deus ex Machina: Lavender Castle itself sometimes saves the crew from otherwise inescapable situations.
- Eyes Do Not Belong There: Captain Thrice has a third eye on his nose.
- Instrument of Murder: Dr Agon uses a laser trumpet in the first episode.
- No Sense of Direction: Sproggle, who often has trouble telling his left from his right.
- Percussive Maintenance: Isambard often applies this to the Paradox's engine.
- Pirate Parrot: Short Fred Ledd's robotic parrot Tin Lizzy.
- Purple Is Powerful: Lavender Castle sometimes manifests as violet energy that will help the crew of the paradox when things go really south for them.
- Reports of My Death Were Greatly Exaggerated: Said word for word by the Guardian in Raiders of the Planet Zark.
- Space Pirates: Short Fred Ledd and his robotic parrot, Tin Lizzy.
- Verbal Tic: Tin Lizzy often has a habit of copying what Short Fred Ledd is saying, which Short Fred Ledd finds really annoying.