“People always ask me, what’s it like inside your head?” So runs the strapline for Sisterson Foods, which I can best describe as an hour-long video montage crossed with an epic beat poem. None of us can ever fully answer a question like that one, but by the end of the show we do have an inkling of what it’s like to be the eponymous Max Sisterson - and of the conflicting, often destructive, voices within his own brain. It’s a little bit ramshackle and I’m not convinced the combination of media entirely works yet, but there’s no doubting that the insights it offers are both powerful and crucial.

Max Sisterson is a real person, and he’s there on the stage - though I’m not completely certain it’s his real life we see portrayed. Let’s assume that it is. Projected behind Sisterson, a continuously-running video shows images from his recent past: parties filmed on a phone, a noticeboard filled with theatre tickets, music videos and TV interviews with particular meaning for him. The video montage is deliberately fractured, but it has a pace and pattern of its own, with occasional contemplative sequences balancing the rapid-fire imagery.

Sisterson himself doesn’t speak, though it seems he wrote the words that we’re hearing. The delivery belongs to Aidan Napier - a striking and authoritative performer, who keeps the energy up and the timing precise throughout the articulate monologue. The script is poetic: rhythmic, occasionally rhyming, unafraid to hit both rhetorical heights (“I’m on Mount Olympus and I’m arguing with Zeus”) and the lowest common denominator (“dick pics” are mentioned just a couple of lines later). The goal is to bring us to the heart of an oscillating internal monologue, and on that count both script and performance unambiguously succeed.

There are scenes of joy and hope - one montage of cutesy scenes from movies is accompanied by a prayer to love itself - but moments of deep darkness come suddenly. Sisterson’s inner voice is often a hostile one, and the poem explains with straightforward candour the paradoxical actions it drives him to. He hates himself, the script explains, so he does nice things for other people in the hope that they might like him. Insights like that one form the heart of Sisterson Foods, and they’re all the more effective because they’re so clearly told.

Yet there’s something about the structure of the show which doesn’t quite work for me. There are two live actors in the room, but with so much happening on the screen, I seldom looked at either of them - reducing Napier’s performance to a voice-over for a video, which I could just as well have watched on YouTube. The slightly awkward shape of the space might not have helped - it forced Napier to stand very much out of the audience’s sightline - but all the same I wanted him to be more present, to interact with the projections somehow.

The gambit of having Sisterson sit silently on stage has the makings of something moving, but the truth is that I didn’t really get what it was aiming to convey. Again, with the eye-catching video playing all the way through, I found it a bit too easy to forget he was actually there; possibly that’s the point, but if so it doesn’t come out as a particular theme of the monologue.

A couple of glitches, such as captions disappearing off the edge of the screen, were easy to forgive on an early outing for a relatively new show. All in all then, Sisterson Foods is an eloquent and intelligent show, speaking the truth clearly without lecturing or spoon-feeding. The video is engrossing, but what I’ll remember most is the driving delivery… which carries us through the difficult themes, reaching out to us, and reaching into our hearts.