Playwright Peter Shaffer’s Equus, the storied 1973 epic about a heinous crime and a troubled child psychiatrist’s investigation into the deeply disturbed mind of the young perpetrator, seems tailor-made for the Blackbird Theatre’s gritty, challenging raison d’être. It’s a show designed to be difficult in both performing and viewing, famous for stripping one of the main characters nude onstage, but also featuring extensive scenes of immersive psychotherapy techniques and bouts of unsettling sexual and violent behavior. Readers should note that the performance I attended was the final preview, and changes have likely been implemented since; to the credit of this intense production and director Sarah Lucas, the work in progress showed little need for improvement, already well within the vicinity of enthralling.

The main thrust of the story belongs to young Alan Strang (Evan Mann), already convicted by the play’s start of savagely blinding six horses, and sentenced to the psychiatric ward of a hospital in lieu of imprisonment. The ensuing plot developments almost entirely concern his treatment by Dr. Martin Dysart (Lee Stille), who seeks to investigate what motivated Alan’s crime as a means to rehabilitate and heal him. What he learns about the young man’s fanatic devotion to horses, and his conflation of religious doctrine and burgeoning sexuality with respect to the beasts, is as disturbing as it is comprehensible. Mann’s work as Alan shows a believable opening up to treatment, beginning with (and reverting to) a murderous catatonia that falls away with growing trust. The pair works together splendidly, with keen pacing and an underlying camaraderie that helps their trajectories to dangerously merge; Stille’s exploration of his character is a perfect stand-in for the comprehending and connecting audience as he fights the dangers of career fatigue and complacency, feeling belittled in the face of Alan’s vibrant —albeit demented — life and beliefs.

The narrow world of the hospital ward is expanded by characters that appear in real time and flashback, slowly clarifying both Alan’s damaged worldview and Martin’s deep-seated doubts. Changes in space and time are guided by lighting designer Emily Clarkson’s deliberate cross-fades through Shaffer’s ambitious metaphysical shifts, which Lucas uses to great effect in releasing the characters from the constraints of literal staging. As the boy’s parents, Amy Griffith and Tom Foley illustrate a divergent, mistrustful couple whose respective pro- and anti-religious approaches to childrearing begin to set Alan’s attitudes into startling perspective. Martin finds a foil in magistrate Hesther Salomon (Brenda Lane), whose simplified take on the case gives the therapist a sounding board for his own complexities as he envies the dangerous but pure passion of his client. Sean Sabo gives his unnamed horseman an irreverent ease that gives added dimension to an early defining memory. Alysia Kolascz is appropriately stern as the expository nurse, but excels as Jill Mason, whose obvious interest in Alan dually promises and threatens release from his childish, overwhelming sexual constructs into something more conventional and reciprocal. The depth of Jill’s appeal and her ease in relating to Alan are necessary to drive the emotion of the final scene, and Kolascz and Mann certainly deliver.

When not taking part in a scene, the cast remains engaged, seated in a line along Barton Bund’s dark, claustrophobic set — not quite neutral, the characters are subtly but intriguingly betrayed by what they choose to watch. However, the ensemble’s strongest work lies in group scenes in which they bring life to the horses that so transfix Alan. Clad in bodysuits amended by abstract tails and twining wire masks evoking a horse’s head and muzzle (masks designed by Bund, costumes by Luna Alexander), the actors generate the look and sound of a stable environment with precision. A combination of commitment and excellent movement coaching gives the horses the majesty and importance the story demands; even viewers who know what happens are likely to find themselves engrossed by this extreme close-up display. In lesser hands, these crucial enlightening scenes could easily come off as ridiculous, but Lucas and the cast are anything but as Alan engages with the horses, recounting fantastic episodes of his growing fervor and ecstatic spiritual and physical communion with the animals.

The discomfiting dimness of the SH\aut\ Cabaret and Gallery space is maintained through the pre-show and intermission, given additional intensity by John Diorio’s unobtrusive but insistent soundtrack. This is a long play, and consequently a long production — its two acts stretching near to three hours — but Shaffer fills it with two intersecting protagonists, whose concurrent stories are each complete and fascinating enough to be its own show. Moreover, this Equus is an accomplishment of direction, acting, and design, working in concert to ensure that viewers will leave not exhausted by boredom, but spent by storytelling that desires no less than total attention and consistently earns it.