A narrator with a book recounts extraordinary fairy tales with a pivotal role for Wallace Shawn, but boy are we a long way from “The Princess Bride.” Disconcertingly tender accounts of bestiality and other disarming sexual reminiscences fill the maverick playwright’s “Grasses of a Thousand Colors.” Cross the masturbatory frenzy of early Philip Roth with Edward Albee’s “The Goat, or Who Is Sylvia?” and you’d still only find yourself on the starting blocks of Shawn’s long and uniquely disquieting dramatic journey.

Playwrights use a variety of means including prescriptive stage directions or exacting punctuation to ensure the safe passage of their ideas from page to stage. Shawn goes one further: He writes the central role for himself. That’s peculiarly pertinent given that the play is, in part, a meditation on what might happen to society’s sense of self.

Outfitted in a dressing gown and cravat, Shawn appears onstage at a lectern with the houselights initially still up to chat about his newly published memoirs. His character, Ben, is a leading scientist who rose to prominence by facing the twin primal instincts of humankind — “the need for food and the need for sex.” Realizing that the second was less of a problem, he solved the first: “We figured out ways to create food where there’d been no food.”

Ben’s solution is far from merely genetically modifying crops. He has altered the food chain and, with amused pride, shows an image of his younger self gamboling with Rufus, a dog: “The very first large mammal ever to be raised entirely on the meat of members of his own species.”

But his radical answer to the food problem has, we gradually discover, profoundly distorted society. This becomes clear as his amiable lecture-demonstration is interrupted by video images of his erstwhile partner Cerise (a positively feline Miranda Richardson), who then arrives on stage to interrupt the extended monologue.

She’s followed by the other two women in Ben’s life, his long-term mistress Robin (Jennifer Tilly) and his young lover and carer Rose (Emily McDonnell), each of whom presents the audience with memories of their intermingled lives.

Only one brief scene in Andre Gregory’s evenly paced production moves into traditionally acted drama as Tilly’s comically knowing Robin pulls a knife on Ben because she has had enough. The remainder of the evening is a succession of direct addresses — descriptions, remembrances of things past and fairy-tale reveries of extreme sex — that form a horror story. What makes Shawn’s script and performance so arresting is its insouciant charm, so brilliantly at variance with what is, in essence, a warning to humankind about society curdling into self-destruction.

With barriers between species torn down, everything has changed. “I mean, when I was a boy, parents never masturbated in front of their children,” Ben cheerfully observes, in tones of gentle astonishment. “In fact, children never masturbated in front of their parents!”

As in traditional fairy-tales that juggle animal characters with anthropomorphism, Ben’s self-revelatory, highly explicit — and often amusing — monologue takes in an intense sexual relationship with Blanche, a beautiful white cat. And that’s only the beginning as unbridled sex becomes ever more central to life.

Appropriately, after the second intermission, sickness has fatally taken hold of the doomed characters. But although the dying fall is necessary for the thematic structure, the strain has begun to show. The spell wears off and the evening unravels.

The drawn-out weakness of the play’s ending, however, points up the stealthy power of what has preceded it. The quiet self-confidence of Shawn’s singular dramatic voice allows him literally to tell a story that keeps the beguiled audience hanging on his words.

Grasses of a Thousand Colors

Royal Court Theater Upstairs, London; 93 seats; £15 $23 top

  • Production: A Royal Court Theater presentation, in association with the New Group, New York, of a play in three acts by Wallace Shawn. Directed by Andre Gregory.
  • Crew: Set, Eugene Lee; costumes, Dona Granata; lighting, Howard Harrison; sound, Bruce Odland; projections, Bill Morrison; production stage manager, Tariq Rifaat. Reviewed May 16, 2009. Opened, May 18. Running time 3 HOURS, 15 MIN.
  • Cast: Ben - Wallace Shawn Cerise - Miranda Richardson Robin - Jennifer Tilly Rose - Emily McDonnell
  • Music By: