In a rehearsal room in Plymouth, a woman is delivering an incantation. It sounds like a spell, a ritual to ward off catastrophe, but actually it's just the shipping forecast, performed in a beguiling manner. Elsewhere, two actors are conducting a duel, but with scissors, paper and stone, just like the children's game. And in another corner, a cheesy dance is being created amid much laughter.
This isn't just a bunch of grown-ups fooling around, however. This is serious stuff: a rehearsal for the latest show from Wildworks, a company that creates striking outdoor performances that tap into myth, play with ritual and connect audiences to a very specific place. "We are simply searching for ways to tell a story," says director Bill Mitchell. "We don't give people lines to learn - we give them a structure to learn. It's the structure we're looking for now."
He sighs. "We've been planning this show for two years and we're performing it in just over a month. At the moment, we still don't know where it's going. But we thrive on uncertainty. It's all about holding your nerve. The longer things remain fluid, the more interesting the outcome."
Normally, by this stage, Wildworks would be working on site. Past sites have included a Maltese fishing village, an abandoned department store in Colchester, and clay pits in Cornwall. But the site for The Beautiful Journey presents particular difficulties because it is the Devonport Dockyard, protected by an infamous high wall. Nicknamed the Berlin Wall, this forbidding barrier was built after the second world war, as the military expanded the local navy base and dockyard. Its construction ripped the heart out of Devonport; the community, which had been devastated by German bombings, gave up its view of the sea for the sake of national security and the prospect of secure employment. Generations grew up by the sea but unable to see it - and unaware that the area behind the wall had once been the bustling heart of the town, home to the pubs, cinemas and dancehalls where their parents and grandparents had met.
Fifty years on, Devonport has never regained its pre-war prosperity; unemployment is rising and the naval base's role is to be scaled back. What future is there for Devonport and its people? That's the question being asked by Wildworks, who, since the start of the year, have been holding tea parties, winkling out stories and memories, and recruiting local people to take part in The Beautiful Journey, a promenade performance inspired by The Odyssey that casts the audience in the role of survivors of an unspecified catastrophe. The viewers are as much part of the spectacle as the actors, the conceit being that everyone has gathered to contemplate their futures in a dockside shantytown complete with food stalls and an end-of-the-world cabaret.
For a company used to doing things on the hop, the constraints of working within the high-security environment of the dockyard have been challenging. Even putting in a power socket requires 42 days' notice. While the navy has been hugely supportive (and the show couldn't happen without their blessing), its health and safety requirements mean everything has to be negotiated - including the show's finale, which involves the launching of a boat built with the help of local people and ex-shipyard workers.
"Sometimes the navy seems quite frightened of the sea," chuckles Mitchell, who, with his gold tooth and twinkly eyes, bears a passing resemblance to a pirate. Prior to founding Wildworks in 2005, Mitchell was artistic director of another famous Cornish company, Kneehigh. Like Kneehigh, Wildworks sometimes seems less like a theatre company and more like a raggle-taggle multicultural family. It doesn't so much make plays as hew theatre from a landscape and the memories of its inhabitants. And it asks the questions that hurt. How do you create a future when the past has been lost? If you had to leave home, never to return, what would you take? Should you let a loved one leave? These are questions the people of Devonport faced during the war and are still facing today, in a place where a sense of belonging is being lost.
Wildworks are used to working with embattled communities, even making theatre in war zones. In 2004, the company was given permission by the UN to put on a show in a derelict taverna in Cyprus, closed because of sniper fire on the Green Line buffer zone separating north and south. Actors and audiences from either side of the line came together for performances that ended with the image of an angel flying over the divided island. And the extraordinary Souterrain, which premiered in 2006 in the dying village of Stanmer near Brighton, was inspired by the grief Mitchell and his partner, Sue Hill, felt when her parents died within a month of each other. Drawing on the Orpheus and Eurydice myth, Souterrain was a heartbreaking meditation on letting go; it played at sites across Europe, gathering along its way 12,000 luggage labels on which audience members had written thoughts.
No Wildworks show is ever finished; they are works in progress, evolving as they encounter new landscapes and new communities. After Devonport, a different version of The Beautiful Journey will be created on South Tyneside, drawing on its people's hopes and concerns. "We tell stories and help people to remember their own stories," says Mitchell. "Our stories and our memories are what make us human. We mustn't lose them."
• The Beautiful Journey is at Devonport Dockyard from 2 June. Box office: 01752 267222. At South Tyneside from 28 July. Box office: 0191-454 1234.