FIRE ISLAND - "The Dying Gaul," a play by Craig Lucas, being given by artistic director Richard LaFrance's Island Repertory Theatre Company at the Tides Playhouse through September 15, is, thanks to the conspiracy of author, director and actors, both painful to watch and too compelling to turn away from. It reveals the pain that motivates its most heinous characters as well as the desperation that drives its sympathetic figures to commit horrific acts and its action--set in and around Hollywood, at the dawn of the protease inhibitor era, which changed AIDS from a certain death sentence to a chronic, but often manageable condition--runs the gamut from undying love to incredible cruelty.

In the play, Robert, an aspiring screenwriter, has written a script, "The Dying Gaul," which has caught major stars' attention, and producer Jeffrey's company wants to film it. Robert's lover has recently died of AIDS and the script, in which he and his late partner figure, loosely disguised, stands a tribute to their relationship, which closeted bisexual Jeffrey insists must be changed to a heterosexual one to make the film more commercial. Every de-gaying alteration Jeffrey demands, should impoverished Robert be tempted to sell out for the million dollars dangled in front of him, further violates the sacred memory of that past union. Jeffrey and Robert's multi-layered relationship, as sex partners as well as employer and employee, complicates matters.

The Internet is in its infancy and Elaine, Jeffrey's wife, striving to learn about the life luring her husband away, finds out which chat room Robert haunts and, adopting a most significant male persona, manipulates Robert with icy calculation. Dr. Foss, Robert's therapist, is well meaning, but also has issues of her own. The language and precepts of both Buddhism and psychotherapy inform the play.

Rhett Kalman is the vulnerable Robert, whose grief might make him seem gullible in the extreme, were it not so palpably authentic and familiar to those of us who have lived through similar situations. Kalman makes Robert's drive to exact and justify all but unconscionable revenge thoroughly credible as well.

If Jeffrey and Elaine, as played by Dennis Callahan and Leslie Cloninger, are not modern drama's answer to Macbeth and Lady Macbeth, I don't know who would be. Callahan and Cloninger chillingly depict this couple as ruthless and proud, their hubris destining them inexorably for a fall, but also give us insight into the hurt that impels them to act as they do.

Michelle Coffaro makes a sensitive Dr. Foss, almost self-sacrificing in her generosity and thoughtfully rationalizing the unreasonable as a product of her own subconscious desire.

The effective unit set and lighting are by Michael Spina.

"The Dying Gaul" may, at times, make you feel as if you've fallen into a snake pit and can't get out, but, rest assured that you won't be bored. Performances are on Fridays and Saturdays at 8 p.m. and Sundays at 7 p.m. Tickets, at $25, are available at the Island Rep table in front of Island Breeze, at the Tides box office just before performance time, or, by credit card, by calling 631/597-9439.