Mark has outfitted his underground shelter with all the necessariesbattery- powered radio, bottled water, propane stove, blankets, and now, his pretty co-worker Louise (Loo Brealey). A suitcase nuke has decimated a good bit of London, Mark tells Louise when she awakens in his emergency-lamp-lit lair. They'll need to remain inside for at least two weeks until the worst of the fallout has subsided. But Louise needn't worrythere's plenty of food and even a Dungeons and Dragons board game. "I've made you a character," Mark cheerily explains. "She's an elf." Louise despairs. Dennis Kelly's hermetically sealed two-hander, a success at last summer's Edinburgh Fringe, offers an awfully discomfiting entertainment. Indeed, several members of 59E59's matinee audience exited, rather noisily, as the power dynamics grew more volatile and the physical and emotional violence increased. Kelly does seem to delight in provocation, but he and director Roxana Silbert shade his script so that even extremes have an air of inevitability. Skinny-legged and stick-out-eared, Mark, played with creepy merriment by Tom Brooke, is precisely crafted. Kelly doesn't fare as well with Louise, however. He offers her a few inspired moments of defiance and piss taking, but mostly casts her as victim and foil. Nevertheless, the piece offers an unnerving reminder that dungeons and dragons occur in many guises, as does terrorism.