“You will feel as if you’re going to die, I guarantee that,” promises the poster for Hearts on Fire, a new piece of immersive theatre inspired by a real-life disaster at a spiritual retreat. I didn’t feel like I was going to die, but I did feel like someone else might, during this claustrophobic and visceral production. The events that this play fictionalises shockingly only happened a few years ago: in 2009 the motivational speaker and author James Arthur Ray held a retreat in the Arizona desert, promising his attendees a cleansing, enlightening and life-changing experience for their whopping $10,000 fee. The five-day programme culminated in a few hours spent in a ‘sweat lodge’ where three people died. Ray has since been convicted on three counts of negligent homicide and sentence to a two-year jail term.

Adam Usden’s powerful script elucidates how this scandalous occurrence came to pass, looking at the ideologies and motivations of both Ray and his followers. Nigel Barber as Ray is charismatic and grotesque in equal measure, commanding the full attention of everyone in the room with seeming effortlessness. When he delivers his first neo-mystical, pseudo-scientific speech, despite all the nonsense there are moments of rational argument and one can see how people became taken in; one of Ray’s oft-repeated phrases is “what you think about you bring about”, an inspiring thought if one ignores its ability to be transmuted into something dangerously self-reliant and to lead to hideous self-blame.

We are first welcomed into the space – a hippie tent with coloured canvas walls, sand on the floor and wooden benches and cushions to sit on – by Ray’s assistant Grace (Sasha Fisher). Fisher portrays her chirpy, syrupy, all-American enthusiasm with heart and humour. She has a dialogue with Ray in which he creepily and manipulatively tells her to stand up for herself whilst making her feel small and revealing his misogyny by patting her bum. Of course, this side of his personality disappears when his “spiritual warriors” begin to arrive. It would be easy for us to dismiss these characters as desperate and foolish were they not so roundly drawn. Julie Addy, Jessica Martenson, David Scott Roberts and Fiona Whitelaw portray characters that vary in their devotion and scepticism, yet all progress through moments of particular doubt or hope.  Ray’s harsh treatment of one woman, resulting in her not having eaten prior to undertaking the overnight, desert “vision quest”, leads his most devoted pupil Carol (Whitelaw) to break the rules – offering her a piece of illicit chocolate cake. Ray shows no compassion as he launches a tirade against Carol after finding this out.

The final scene is the fated sweat lodge process, with Ray attempting to lead bogus shamanistic chants as he pours water onto coals and the other participants pant and struggle to maintain upright. The room wasn’t as hot as I expected but it was viciously uncomfortable, inciting a truly visceral response; I really did want to get the hell out a few times, which was clearly one of the aims of Hearts on Fire’s creators. But don’t let fear stop you from seeing it! Ali Boag’s superb direction is immersive but doesn’t ask for audience participation and the play is a rare insight into the mind of someone with a serious God complex and a touching portrayal of the lengths people will go to in search of a brighter future.

***** – 5 Stars 

Hearts on Fire is playing at C venues as part of the Edinburgh Fringe Festival until 27 August. For more information and tickets, see the Edinburgh Fringe website.