It begins by disturbing our sense of sight, the kind of blur that makes you first clean your glasses and then wonder whether something is seriously wrong with your vision. The set, a scruffy kitchen with a woman standing with her back to us, slowly comes into focus — a bizarre cinematic technique — and when she turns toward us she reveals a bloody nose, dripping down her mouth, her chin, her clothes. She does not unfold her arms.

The Children, a brilliant and deeply troubling play by Lucy Kirkwood, gives us that rare combination: a serious and intelligent play filled with witty dialogue spoken by serious and intelligent characters. Even more surprising and gratifying is the fact that Kirkwood is quite young, but, like Beckett, can write about aging and decline long before experiencing that endgame.

The woman bleeding in the kitchen is Rose (Francesca Annis), a nuclear physicist who has come to visit old friends and colleagues; Robin (Ron Cook), her former lover; and his wife, Hazel (Deborah Findlay).  Nearly 40 years ago, they all worked to build a nuclear reactor. Significantly, it's next to the ocean: they placed the emergency generators in the basement. "The disaster" (like Japan's Fukushima nuclear catastrophe) happened after an earthquake and the tsunami that followed, leaving this coast of England uninhabitable, radiation "hanging in the air, a sort of a sort filthy glitter suspended."

These three sixty-something scientists realize that, having made a grievous error, they are responsible for fixing it. Rose is recruiting a team of 20 aging engineers so that young engineers won't have to sacrifice their lives to repair their elders' mistake.

Each of the three superb actors, reprising their London production at the Royal Court, delivers a complex performance, so taut, so believable, so warm, that you feel included in their reunion.  As we're slowly let in on their history, we learn the depth of the play's opening line, "How are the children?"  Like Joe Keller's learning that they are "all my sons," this carries a powerful sorrow as well as a powerful indictment of a generation that has left a terrible legacy.

The two women have made very different choices in how to live: Hazel, who has four children and four grandchildren, has committed fully, desperately, to living — yoga and salads — while Rose, who has no children, still smokes and drinks.

Their former rivalry for Robin gives their conversation bite as we watch this long-ago triangulated relationship reawaken: No matter how global the issues, it's always, finally, personal.

Kirkwood's dialogue is fast and funny, and the jokes are very dark, literalizing clichés ("come hell or high water") as they dance together and our hearts break for them. The Children isn't bitter or resentful; it looks death and crisis heroism right in the eye, and I found myself filled with admiration for these three characters, for these three actors, and for this excellent playwright, all under the skillful direction of James Macdonald.

The Children. Through Feb. 4 at the Manhattan Theatre Club, Samuel J. Friedman Theatre, 261 West 47th Street, New York.