Pablo Schreiber and Jennifer Carpenter Photo by Joan Marcus.

The two questions that most permeate the action are: "What is Kayleen and Doug's relationship?", and "What does each want their relationship to be?" When we first meet them, in an elementary school's nursery office, they appear to be little more than rough-and-tumble friends, boys and girls being boys and girls before they get weighed down with any sexual baggage. Doug (Pablo Schreiber) split open his face while mimicking an Evel Knieval bike move riding off the school's roof; Kayleen has a stomach ache, but a gentle being that puts Doug at ease as she touches his hurting head and picks specks of gravel out of his palms. These are two young people who find in each other a kindred spirit of the type that rarely occurs in nature.

Time progresses, of course, but the chemistry they share does not seem to. As he falls victims to fireworks and freak accidents, and she to rape and self-abuse, each becomes increasingly for the other a healing force: she to his body, he to her spirit. Yet because they don't understand or respect the full depths of their powers, they seldom connect in ways that last much beyond the length of each individual affliction. As the scenes unfold (out of chronological order, for no apparent good reason), they remain apart from each other for sometimes years, letting their lives and loves unfold unfettered by the other's influence: he goes off to college, she moves in with another guy, he gets engaged, she has it out with her father. But neither learns how to completely satisfy themselves and each other, which causes each new discovery to predict some different kind of doom.

Uneasiness of this sort can make for an absorbing character study, but only if the characters themselves are richly observed. By virtue of their resilience, if nothing else, Doug and Kayleen are highly likeable; the more we see them, the more we want them to succeed and survive against skyrocketing odds. (One scene in particular, set when both are 18 and Doug has developed a habit of defending Kayleen's honor from some nasty young men at school, suggests their unusual union may, and may have to, work.) But if Joseph has sufficiently sketched out the pair's latent charm, he hasn't provided enough depth to give it much solid, emotional meaning.

Unlike the central figures in his earlier works, Huck & Holden and Animals Out of Paper, Doug and Kayleen cannot admit even to themselves what their most intimate needs are—and it doesn't emerge organically from their bruising-and-battering badinage. Leaving aside the issue of any lingering romantic undercurrents that may exist between them, we don't get to know very much about either. His family is loving and hers is not, both make poor dating choices, both take unwise physical chances in pursuit of spiritual absolution they can't find elsewhere. But the goals they seek or their rationales for looking for them remain mysterious from beginning to end.

Director Scott Ellis's production moves with a clean, mechanical efficiency, on a gleaming Neil Patel set that looks like a cross between an emergency room and a space-age aquarium. Carpenter transitions effortlessly between ages and mental states as she creates a woman who externalizes every indignity she suffers, but displays no softness to temper Kayleen's pervasive angst; Schreiber looks and sounds identical and identically uninvolved in every scene, often blaring his lines at a sing-songy shout that renders Doug even more unrounded a personality than he already seems. Both actors come across as too good-looking and well-adjusted to need to play these kinds of games; the play cries out for more dangerous, out-of-the-mainstream talents to convince you these characters can only find salvation through trails of literal blood.

Then again, despite the myriad oozing wounds on display here, blood is what's most lacking. Doug and Kayleen derive some satisfaction from the thrills of risking life and limb (sometimes intentionally, often not), but without a stronger representation of their underlying passions, it's all more gratuitous than gratifying. If Joseph's goal is, as it seems to be, to demonstrate the self-destructive lengths to which we'll go to find ourselves when we discover how alone we truly are, the duo's motivations need to be much clearer than they are. As it is, each new ailment sends a chill down your spine, your leg, or coursing through your hair, as you consider—if only for a moment—how it might feel to happen to you. It's that you never find yourself considering how Doug and Kayleen feel inside that proves most injurious to Gruesome Playground Injuries.

Gruesome Playground Injuries
Through February 20
Second Stage Theatre, 307 West 43rd Street at 8th Avenue
Tickets online and current performance schedule: Second Stage Theatre