The star of April is a self-styled self-help guru, offering solutions to all your problems through the medium of positivity. The satirical tone maintains itself for most of the running time, ridiculing multiple aspects of those YouTube personalities who promise foolproof advice to improve viewers’ lives. But there is a lot more to Carrie Marx's solo show than that - and the script takes several unexpected and quite dramatic turns in the latter stages.

Audience members are asked on arrival to submit problems for April to solve during the show, which provides the impetus for an amusing series of positivity exercises. In between those set-pieces, April regales us with her own brand of perky, over-bright wisdom; as April, Marx commands the stage, switching rapidly from friend, to lecturer, to spiritual guide, and back again. If you’re sitting on the front row, be prepared for her to get up close and personal as she engages the audience frequently in her presentation.

The workshop format works well, and April is a highly engaging presence - though there is a sense from early on that all is not as it seems. Her perfect positive persona starts to show some cracks, and the inclusion of a rather unsettling video part way through raises questions about her allegiances. If you pay careful attention to the meanings of the sigils as they flash up, you can find some clues to April’s true nature.

The first few minutes of the show were a little off-putting for me, as the sound balance and use of voice distortion make it difficult to distinguish the words of April’s opening song. But the cleverly-orchestrated nonsense of her positivity message neatly satirises those who use pseudo-science to support their theories, and the promise of miraculous secret knowledge to sell their books. There is a suggestion that April may have a neurological disorder and, while the way this is initially played for laughs did make me uncomfortable, it's revealed as the set-up for satisfying and powerful pay-off later on.

Just at the point where it starts to feel like it’s been going on too long and there isn’t enough substance to round out the show, the narrative changes tack, adding multiple new layers and making what April is trying to do suddenly much more interesting. The commentary provided at the end of the show also suggests that Marx has an intensely personal connection to the material, which makes it resonate even more. Overall, April is well-written, brilliantly performed, and both hilarious and challenging. And you get a free badge!