It may be a time capsule of a play, but the sterling new Broadway revival of Larry Kramer’s The Normal Heart reveals that it has lost none of its urgency or power. A semi-fictionalized account of the beginning of the AIDS crisis and the efforts of a group of dedicated activists to spur the city and country into action, this work, first seen in 1985 in a landmark production at the Public Theater, is relentlessly gripping and moving.

This version co-directed by Joel Grey and George C. Wolfe began life as a one-night benefit reading last November. Newly staged with several of its roles recast, it marks a long belated Broadway debut for the work.

The central character, based on the playwright, is Ned Weeks, whose fierceness and oft-expressed hostility soon put him at odds with both the authority figures he was lobbying and his colleagues in the organization (the Gay Men’s Health Crisis) that he co-founded.

Joe Mantello, in his first acting gig since his starring turn nearly two decades ago in the Broadway production of Tony Kushner’s Angels in America, is absolutely superb in the leading role, leading one to hope that this now celebrated director (Wicked and Take Me Out, among many others) will return to performing on a more regular basis.

He’s well supported by a sterling ensemble that includes John Benjamin Hickey, heartbreaking as Ned’s New York Times journalist lover who contracts the disease; Lee Pace, as the more diplomatic co-head of the organization; Jim Parsons (TV’s The Big Bang Theory), sardonically funny as one of its impassioned members, and Ellen Barkin, as the polio-afflicted doctor distraught over the growing number of her patients becoming afflicted. Other roles are well handled by such pros as Patrick Breen, Mark Harelik and Richard Topol.

The urgently written piece borders on being polemical while sacrificing none of its human drama. Among the evening’s highlights are two wrenching monologues: one by Pace in which his character describes in wrenching detail the death of his lover, and another featuring Barkin delivering an increasingly intense, showstopping harangue about the refusal of the government and media to recognize the severity of the epidemic.  

It all proceeds with the urgency of a great political thriller, that like the film All the President’s Men, is completely involving despite the fact that the audience essentially knows what’s going to happen.

Simply staged with a minimum of props, the production features a series of projections depicting the names of actual victims of the disease. As the events of the play--which takes place from 1981 to 1984--progress, the names swell to the point where they cover the entire rear and side walls of the theater.

As they leave the theater, audience members are handed a letter by Kramer in which he strongly argues the case that the plague is far from over and that much more work needs to be done. It’s a comforting reminder that this impassioned activist, now in his mid-seventies, is still fighting the good fight.

Golden Theatre, 252 W. 45thSt. 212-239-6200. www.Telecharge.com.