The ambitious production is a form of LARP—or live action role playing—a pastime that brings role-playing games like Dungeons and Dragons or World of Warcraft to life. Stereotypically, LARP includes dressing up like an elf and running around a local college green, hitting others with foam swords.

Nordic LARP takes a more artistic, less competitive approach. It chooses stories beyond traditional fantasy fare, and its participants spend significant amounts of time making sure their (often assigned) backstories and costumes are accurate. The craft is unique, say the editors of The Foundation Stone of Nordic LARP:

It spends more time telling stories that emphasize naturalistic emotion, it emphasizes collective, rather than competitive storytelling, and it takes its stories fairly seriously much of the time.

One famous Nordic LARP, for instance, examined what it was like to live with AIDS in the 1980s. Over the course of three days, the event placed its characters at three successful July 4 parties held in 1982, 1983, and 1984. Participants began the LARP not knowing whether their characters would be infected with HIV. By its end, many of the people they were playing had died.

Nordic LARP has spawned conferences and books, and it’s now played around the world. (Its advocates are quick to note that other kinds of LARP are played in the Nordic countries, too.) Inside Hamlet isn’t without precedent, in other words. There have been other interactive productions of Shakespeare’s play, and more traditional productions of Hamlet have been performed at Elsinore, too, by actors including Laurence Olivier, John Gielgud, and Jude Law. But this is the first Nordic LARP interpretation of the story performed at the castle.

The event has been organized by Odyssé, a company that designs and holds participatory events. “We call it LARP tourism—the chance to travel to worlds that don’t exist,” its creative director, Bjarke Pedersen, told me. “[Kronborg] is the best place to do Hamlet. That is why we wanted to do it at Elsinore.”

Pedersen and his team have had to refashion Hamlet into something that could be performed as in this particular way. Many scholars traditionally understand the play to be about the hazards of indecision: Hamlet wavers until it’s too late to avenge his father’s murder. But that interpretation doesn’t work as well in a LARP, as participants have to take decisive action to drive the story forward. So the Odyssé team looked for other possibilities. “We fell over what is called the Marxist reading of Hamlet—that Hamlet was a brilliant mastermind who corrupts the court from the inside. It turns Hamlet into a man of action,” said Pedersen.

Writing a LARP is hard because writing as such isn’t really possible. Odyssé can design characters so that they’re likely to come into conflict with one another, and can structure the major events of the story so that they create crisis. It can also use stage tools such as lighting to initiate certain events. But it can’t order characters to talk or fight. The task that Pedersen’s team faced was how to turn Hamlet, a five-act story with forward action, into a participatory experience.

Inside Hamlet preserves the major characters—Hamlet, Ophelia, Claudius, Polonius—and the great events of the play. But it has only three acts, each more than four hours long, performed on Friday night, Saturday morning, and Saturday evening. Each act has a theme and a setting. “Decadence,” the first, takes place at a late-night dinner party as the fortress’s gates are closed. (Far away, at Denmark’s borders, Fortinbras and his army have just invaded.) “Deception” is set a few months later, as Fortinbras draws closer and alliances crumble. (“When you live in a place not designed [for it],” said Pedersen, “everything goes to hell.”) And “Death,” the final act, happens as the army prepares to charge the gates.