My Fern Flower is a strangely-named and strangely-beautiful show, which sits somewhere on the boundary between theatre, storytelling, and music. When you net it right down, it’s the tale of two brothers: Jonah, who narrates the tale, and Jim - ten years younger - who needs help that only Jonah can give. But there’s a mythical dimension to it as well: Jim has a free-rolling imagination and a book of collected stories, including one story that the brothers decide must never be told. As the pressure takes its toll on Jonah, he begins to imagine his real-life mission as a fantastical quest, facing monsters and temptations in his search for a miracle.

Jonah York (both actor and character are called Jonah) plays all the parts in the story, including Jim - a hauntingly vulnerable figure in an unfashionable yellow raincoat - and his wittily-drawn extended family. York makes Jonah a likeable, open-hearted protagonist, who begins the show by discussing his favourite flower and, later, shares his pain without a hint of indulgence or self-pity. York is joined on-stage by Adam Michalakis, who provides multi-instrumental musical accompaniment, and credit’s also due to lighting designer Liam Aston - whose work does a lot to set the immersive tone.

Sound, and tempo, are central to the piece; by recording and replaying certain notes and phrases, York and Michalakis gradually build an evocative soundscape, which neatly and unobtrusively complements the story. They use the technique sparingly, and there are moments of quietness when they’re needed, but the return of the rhythm is always a resonant reminder of the plot points that have come before. York’s physical performance has a cadence to it too, at one point bursting into a thrilling full-bore chase scene which may or may not have been an intentional homage to Temple Run.

But it’s the more sensitive scenes that make the biggest impact, as Jonah finds himself confronted by an utterly impossible dilemma: a choice between two life-changing events, and two loved ones who both need him. It’s a heart-rending scenario, and York draws out our full understanding, even as he slips into the mythical world of Jim’s story-book. The link between story and reality is cleverly thought-through and neatly revealed, delivering a warning - as all the best fairytales do - against grasping too hard for the things you desire.

My Fern Flower is a brand-new show, and one or two things do feel a little unbalanced at this early stage. The first tragedy to strike Jonah and Jim’s childhood passes by quickly; it’s a shocking event which would surely define their lives, yet it’s detailed so briefly that I’m still not sure if it was a literal description or a metaphor. The opening also introduces us to an array of characters, each represented by clothing hanging on a hatstand, but in the event many of those figures don’t feature all that much; it’s an effective icebreaker, but it set me up to expect something that the show never intended to deliver.

What it does deliver, though, is 50 minutes of stylish and evocative storytelling, combining striking and surprising visuals with a rich, expressive soundscape. It tells deeply moving story which never descends into pity, and even finds cause for happiness and hope. The mythical undertones show a deft touch for allegory… and with its powerful script and performance, I’m certain that My Fern Flower will stay with me for a long time to come.