'We need stories about monsters. They remind us what is possible,' storyteller Seth Kriebel remarked, as he opened this intimate, informal and innovative night of theatre. Stories about monsters are indeed the ones we return to again and again, and Beowulf is perhaps the quintessential monster-slaying story. It's also a storyteller's dream, lending itself to endless reworkings and adaptations - but Kriebel's unique, choose-your-own adventure version is probably the best I've seen.

I followed the crowd into the Old Fire Station theatre to see that the first seven audience members had already been enlisted to participate in the performance. Two men were sitting at a table strewn with shot glasses, playing the role of Kriebel's friends. On the other side of the stage was a row of five chairs, occupied by some rather perturbed-looking people who would go on to act as spokespeople for the entire audience. Kriebel immediately set us at our ease (those of us who weren't on-stage, anyway), opening with an introduction of the story and the promise that it would end with a dragon.

The story began, and the cleverness of Kriebel's take on this ancient story soon became apparent. Speaking as Beowulf, he described a beach with a road that led up towards the cliffs, using Viking kennings to build up a vivid picture in the minds of the audience - then turned to our five representatives on stage and asked 'What should I do?'

And so the choose-your-own adventure portion of the evening began. The five audience members soon began to have fun with Kriebel, leading him in circles through different locations, while the rest of us shouted out suggestions. Fight scenes between Beowulf and Grendel, Grendel's mother, and the dragon were first hashed out with his two 'friends' over at the table, then described to the audience in a sequence as exciting as any action film.

Kriebel's performance was masterful, blending memorisation of a staggering number of scenes and settings with seamless improvisation (a very necessary skill when dealing with an audience that repeatedly went rogue!). He told the story, and the story behind the story, in a way that made it feel fresh and new, mingling ancient storytelling techniques with a Dungeons and Dragons-esque, interactive structure that made the hour's performance fly by.

No two performances of Kriebel's Beowulf will ever be the same - while we know that Beowulf will always fight two monsters and a dragon, the way he gets there depends on the audience. If you get a chance, I urge you to go along and take part in one of the most exciting performances I've ever experienced. Just watch out for dragons.