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Describing a play or movie as a “lecture” sounds like an insult, but sometimes a lecture can be, to use the language of this one, illuminating.

Masterpieces of the Oral and Intangible Heritage of Humanity (Yes, they mention how “unwieldy” of a title that is. No, that doesn’t make it any less awful.), going on now until April 7 at the Signature Theatre, concerns itself with what is salvageable and what is redeemable — in art and in human beings — when the fires, floods, and wars creep in. Directed by Nadia Tass from a new script by Heather McDonald, Masterpieces deals exclusively with heavy matters, such as blood, torture, and 17th century Dutch painting. It’s a lecture, but a smart one.

The entire world has been at war for a century, and things are a bit of a mess. Even as the bombs and bullets can still be heard offstage, three women — a nurse, an art expect, and their soldier jailer — are given the task of restoring a badly damaged Rembrandt. Or else. All three have painful pasts, uncertain futures, and welcomely complicated motivations, carving out space for great performances from three reliable D.C. actresses.

Felicia Curry, whose work I deeply enjoyed in Arena Stage’s Disgraced and Nina Simone: Four Women, excels with the least sympathetic job as Mitra, a captor brimming with rage. Yesenia Iglesias brings the same unsentimental sensitivity to the role of Nadia, a nurse with a secret or two, that she did to parts in Constellation’s Arabian Nights and Caucasian Chalk Circle. And center stage is Holly Twyford, who last year nearly stole Folger’s King John, mixing a fine brew of intellect and passion as the restorer-in-chief.

Production values are equally stellar, particularly the lights and sound from Sherrice Mojgani and James Bigbee Garver, respectively, who fill Signature’s black box space as if it were the Cosmic Cube. The black box intimacy is less kind to fight choreography, however, as the three actresses grapple and batter each other just a few feet from the crowd.

And the script, which takes too much pleasure in its second-half clever dialogue reversals, piles on the drama to towering levels. As a philosophical discussion, it never falters, but the tears and screaming get to be a bit much.

This play isn’t a masterpiece. But it’s definitely worth saving.