Maria/Stuart, by Brooklyn-based playwright Jason Grote, is a cleverly built, well-concealed pit trap. At first, the play seems like a pleasant stroll through a family of comical, middle-class eccentrics—in just a few steps, it plunges into a dark subterranean maze.

The story begins innocently, with an awkward, lovable nerd named Stuart talking on the phone, pitching his ideas for comic books. He fiddles with his pen and excitedly describes Russian gangster capitalists fighting Chekhovian superheroes: the Three Sisters (who communicate telepathically), the Seagull (has big wings), and Uncle Vanya ("a jolly, fat guy who's ex-KGB and doesn't have any superpowers at all"). Brandon Ryan plays Stuart as anxious and squirmy, but not at all repulsive. He's the kind of guy for whom you hope life pitches softballs. Life doesn't, of course, and Stuart erupts into a storm of squeaks and tics when he's uneasy—which is pretty much always.

He has good reason: His mother is a neurotic mess, his aunt Lizzie is an angry bully, and his aunt Sylvia tried to commit suicide by train, botched the job, and now has hooks instead of hands, which she uses to stuff herself with cheese balls and hold half-smoked cigarettes, driving her other sisters crazy.

The family—rounded out by a befogged grandmother and a pretty cousin who Stuart wishes were his girlfriend—is allergic to decorum. Aunt Lizzie (the stern Deniece Bleha) doesn't ask who moved the appetizers at the family dinner party. Instead, she bellows, "Who moved the fucking hors d'oeuvres?" A shape-shifting ghost, who assumes the form of different family members and barks in German, reveals a secret letter, sending the whole nutty clan into a steep nosedive.

Grote describes Maria/Stuart as "a contemporary rip-off" of Friedrich Schiller's Mary Stuart, but Grote's vivid, restless imagination roams far and wide, from vintage superheroes to the wages of incest. The characters bicker and pick at each other, building to a series of ugly revelations and a postfuneral food fight. Director David Gassner has done everything right: He found a surprising, unsettling comedy and mined it and his cast for everything they're worth. This is Maria/Stuart's second production. (It premiered last year at Wooly Mammoth in Washington, D.C.) Here's hoping this isn't the last we'll see of Jason Grote. Or of Brandon Ryan.