Plank

Plank, Alley Cat Theatre, Deane Hall, Caldewood Pavilion, Boston Center for the Arts, September 16. 617-933-8600

Are some 21st century theaters throwing truly original conceptions overboard? Are some venues scheduling somewhat predictable line-ups featuring umpteenth revivals of popular plays and musicals? For many years now, the envelope-pushing troupe Imaginary Beasts has been defying these disturbingly rhetorical questions with highly imaginative Winter Pantos and highly personal and thoughtful takes on works by such different authors as Moliere and Thornton Wilder at the Boston Center for the Arts. Now the new Alley Cat Theatre has brought its own challenging pushback to same old, same old efforts in a strikingly evocative Caldewood Pavilion world premiere called ''Plank.'' While founding artistic director John Greiner-Ferris' dream play may need some tweaking, this inaugural vessel impressively steers clear of safe sailing at the BCA.

Thanks to the brilliantly complementary scenic design of Ji Young Han and projection and lighting design by Barbara Craig, audience members immediately enter the play's richly unsafe atmosphere as though they are about to enter a large rock- bearing ocean themselves. Clearly theatergoers are meant to not only empathize but also identify with forlorn heroine Potpee-played with affecting vulnerability by Poornima Kirby-- who survives a backstory shipwreck by clinging precariously to the title board. Around her in the waves of the ocean design, a quartet of talented cast members-Liz Clark, Sydney Grant , Alan Lokken and Fray Michael Cordero-make the fish, seaweed and waves that alternately seem to greet and challenge her take shape poetically through a variety of gestures and modern dance moves. Ned Singh's sharp sound design enhances this dream tableau with an evocation of whales and their singular sounds. At the same time, a lunchbox with a half-sandwich and a coke materialize for Potpee as well as a large edition of ''Moby Dick.''

Of course, as Potpee begins reading, "Call me Ishmael"-the famous beginning of Herman Melville's masterwork- connects her with the novel's sole surviving shipmate. Once Potpee arrives on land, survival issues expand with talk about climate change and human responsibility. Here of course theatergoers will rightly be thinking about their own feelings and commitments. Taking those thoughts and considerations to center stage are exchanges between Potpee and Orwellian Big Sister- like Mercedes--played with arresting toughness by Adams-and Mercedes' conflicted sidekick Thimble-- captured with fitting insecurity by Kirby.

As Mercedes intimidates Potpee with a hardline interrogation and virtually dismisses her as a "little girl," she may be considering having the shipwreck survivor walk the plank-at least figuratively and philosophically. Pushing the idea of "comfort in a crowd, "she sees safety in "a shared view of the world." By contrast, will Potpee-who lost everything overboard-- survive without having an I-phone, Facebook or even a television? For her part, the unusual heroine suggests that contemporary human beings lack perspective and that "maybe we should have stayed in the ocean." Alluding to Adam and Eve, doctrinaire Mercedes contends that "We belong on land." Director Megan Schy Gleeson sharply paces the exchanges between Potpee and Mercedes so that their ocean-land debate has the volleying intensity of a championship tennis match.

Not surprisingly, Mercedes' right hand woman finds Potpee's embrace of real freedom intriguing. Thimble does not make waves though she finds this survivor's simpler way of life fairly appealing. She may also be emotionally drawn to Potpee. Does their sitting on the pivotal plank together signify a substantive change in Thimble? Look for a revealing surprise in the final stretch.

At one point, there is talk of going around in circles. Audience members may sometimes feel that way about this play. Even so, "Plank" does possess a welcome freshness and healthy food for thought about theater itself. Set sail for the BCA and Greiner-Ferris' worthy stage lifeline.