The scrappy urban garden at the back of Sweet forms the perfect backdrop to this immersive outdoor show. To us it looks untamed, perhaps a little squalid; but our opinion of it doesn’t matter, because this is Caliban’s home. Until, that is, Prospero came, and in freeing the garden’s creatures from one form of servitude merely condemned them to another. Now, twelve years after the events of Shakespeare’s The Tempest, it’s Caliban’s turn to tell the story.

Caliban is played by the ever-impressive Emily Carding - and what a portrayal it is, run through with desperate intensity. It’s not exactly anger (though there’s plenty of that), and it’s not exactly pain (though the rawness hurts at times); it’s more the knowledge that the worst lies ahead, and that nobody is coming to save him. He does have a weapon though, a torn and shredded magic book, the one that Prospero thought he’d destroyed. We learn at the end which spell Caliban means to cast… and we understand, by then, why he’s chosen to cast it.

Carding’s Caliban isn’t a monster, but there’s something subtly non-human about the portrayal. It comes through in the cat-like way she springs onto tables, or her feral scrabbling among the torn pages on the floor. And that distinction is important, because Caliban’s Codex has a message to deliver - about humankind’s interaction with nature, and our plunder of the natural world. It’s a neat interpretation which doesn’t feel too forced, and gives Caliban’s denunciation of Prospero’s manipulative greed a powerful resonance with perspectives of world leaders today.

John Knowles’ script has a satisfying tempo, fittingly penned in iambic pentameters. But a good chunk of that script re-tells the story of The Tempest - and it’s no disrespect to remark that Shakespeare did that better. Perhaps that’s the price of writing a follow-up to this particular play: people think they know it, but it’s not among the very most famous ones, and it’s unsafe to assume they’re truly across the details of the plot. Still, I wonder if there’s scope for a more interesting recitation, a less linear structure to the narrative and a mystery or two held in reserve.

I was also confused about what we, the audience, were actually doing there. Caliban can see us, and talks to us directly, so are we the invaders he’s been preparing for - or just figments of his imagination, maybe? And while the ecological themes are cleverly conceived, their presentation isn’t exactly subtle. I’d have engaged with them more, I think, if I’d had to do some work myself, to draw the parallels between Prospero’s exploitation of the island and humankind’s pillage of Planet Earth.

In the end, though, I come back to that garden - and the life that surrounds us as Carding spins the tale. As she stirred to life at the start of the play, a cat darted out of the undergrowth; during pauses in the monologue, I was acutely aware of birds calling overhead. In more than one way, then, Caliban’s Codex reminds us of nature. And that’s a magic spell of its own.