"Orphans," a gripping play that opened Thursday night on Broadway, is about brothers -- and it's full of the City of Brotherly Love. Alec Baldwin at one point gives a character a gift in a large John Wanamaker bag.

One character confronts another with a copy of the Philadelphia Inquirer, berating him for underlining many of the words. When the sun sets, it drops over Camac Street in North Philly – to be exact, Oak Lane – and it's duly noted in the script.

This is 1960s Philadelphia, where you could get coffee at Linton's or a map of the city from the Philadelphia Transportation Company before it became SEPTA, or get drunk in some corner dive and then kidnapped by a petty thief looking for meatier gains than a stolen wristwatch. That's what happens to Harold, played with a perfectly calculated whiff of con-artistry by Baldwin; he's a mysterious Chicago businessman who's come to Philadelphia to evade people he's apparently duped. Harold wakes up one hung-over morning to find himself tied ineptly to a chair inside a dingy Camac Street row house.

But the real victim, it turns out, may be his kidnapper, an angry, creepy, impulsive guy who doesn't know who he's dealing with.

"Orphans" was written in 1983 by Lyle Kessler, who grew up in Philadelphia and left when he was around 20 to pursue a career in acting, then branched out to write plays and screenplays, including a film version of "Orphans." The play has been widely performed -– Philadelphia Theatre Company was an early producer, a few years after its initial staging in Los Angeles -- but it has never appeared on Broadway until now.

And it's getting top-notch treatment from veteran Broadway director Daniel Sullivan and with sterling performances by its three-man cast. They play out their tale of desperation and discovery on John Lee Beatty's gloomy interior row-house set where two orphaned brothers, now adults, exist like hermits. The older, volatile brother (a tough, menacing Ben Foster) is the supporter of the two. His younger sibling (Tom Sturridge, who in this production moves constantly like an animal waiting to be sprung) is mentally deficient and confined to the house by his brother.

Together, they are stunning social cripples, and also a case study in survivalist care-giving. When you're so invested being a guardian angel, the play asks, who guards over you?

Intrigue and acrimony preceded the opening of "Orphans" – the film actor Shia LaBeouf began rehearsals as the older brother, then was fired after battles over character interpretation; at that point, LaBeouf released private e-mails and trusts were betrayed and blah, blah, blah -- it's now all piffle, because what comes out of the mess is provocative, magnetic theater.

The film and TV actor Ben Foster ("Six Feet Under" as Russell Corwin) makes a powerful Broadway debut in the role he originally tried for but LaBeouf had won; on stage, he is a spring wound way beyond safety. Sturridge, a film actor who has made a mark on London stages, is kinetic and convincing as he leaps, slinks and runs around the living-room set with an animal's grace. And Baldwin easily builds a character who becomes more intriguing with each scene – precisely the way "Orphans" itself plays out as the sun sets over Camac Street.
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ORPHANS is playing in a limited run through June 30, at the Gerald Schoenfeld Theatre, on 45th Street near Eighth Avenue, New York City.