The Witch Garden is more than just your average, typical back garden - it's more like a large and diverse, self-contained magical ecosystem, with fields, forests, rivers, villages and towns - even a castle - spread over its lush and green lands. Harper, the clumsy talking owl lives there, as do Alditha the white witch, the Green Man, and Skoros - the less than pleasant, megalomanic steampunk wizard. When a giant flying teacup appears over the Green Man's nook, Harper is convinced Skoros is up to no good, and reports the matter to Alditha. They discover, however, that the occupant of the teacup (which is really a spaceship in disguise) is actually a humanoid alien called Celeste, who looks about thirteen years old. Celeste hints that the Witch Garden is only a small part of a Class M planet called RY53-6, and seems intent on locating a series of mysterious silver orbs. She has a bio-mechanical alien sidekick called Alpha (who looks like a typical 'Grey' alien). They're Astarians, and together, they're on a mission to find The Sleepers - an Astarian space crew they believe visited the planet thousands of years ago. Near the centre of the Witch Garden, in a town called Enki-Wood, is a monument to the nearest thing the WitchGardenfolk have to a god (Vin Taoo, the Great Gardener). The monument is Stone Hedge, and it's actually the petrified drive system of The Sleepers' dimension-hopping spaceship. When Celeste accidentally wakes The Sleepers from thousands of years of cryogenic sleep, the battle is on, not only to defeat Skoros and free the Witch Garden from his malign and polluting influence, but also to thwart the leader of The Sleepers, who wants to make the planet uninhabited again, as it was when he originally found it. It takes the united efforts of all kinds of WitchGardenfolk, as well as Celeste, Alpha, and some of The Sleepers, to overcome both threats before the main Astarian Fleet arrives, and a deal can be brokered to co-exist with the Witch Garden's newest residents.