Having made a pedophile charming, Bryony Lavery now tries to make death a comedy. In her follow-up to last season’s “Frozen” (which, to be sure, didn’t try for that many laughs), comes “Last Easter,” which does.

Mining terminal cancer for giggles? It sounds like some kind of joke, not a very good one. But Ms. Lavery pulls it off, more or less. She works at a couple of advantages. She has a genuine sense of humor, and knows where to find the funny. Also she avoids doing what you fear she’ll do, using humor to make the show doubly weepy. In “Frozen,” where a woman confronts the man who molested and murdered her child, Ms. Lavery erred by being too chilly. Here, a certain emotional reserve suits the material. She resists the temptation to wallow; she leaves you laughing.

Ms. Lavery made a smart choice of locale. She hasn’t set this story, about a cancer patient and the friends who help her, among stockbrokers, vintners, or academics. June, the dying woman, is a lighting designer. Her friends, Gash and Leah, are a female impersonator and prop-maker, respectively. When they whisk her off to Lourdes on a quixotic attempt at a miracle cure, the story also ropes in an actress, Joy. We are in the world of the stage, a play by and about theatricals.

What draws people to a life in the theater? The sociology of the question is inexhaustible. The profession’s material rewards are scant. The gratification from a cheering audience may be potent, but it’s fleeting. Working in the theater doesn’t just encourage a deep and abiding gallows humor, it’s a requirement. On the evidence presented here, if you know your end is near, and need some fortifying to get through the day, you’d do well to surround yourself with theater folk, people who are expert in the serious business of make-believe.

The action takes place on a rehearsal stage, at the theater where they all work. Hugh Landwehr’s scenery consists of a workbench and tall shelves full of props. (It’s like a rough-and-tumble, backstage version of Derek McLane’s exquisite set for “I Am My Own Wife.”) As the story shifts from London to France and back, there are no scene changes, and minimal props. June may be wheelchair-bound, but we never see it: chairs and some skillful blocking suffice. When the friends drive through mist, a stagehand circles them with a bowl full of steaming liquid nitrogen.

Ms. Lavery blends faith and profanity. “The only thing I find religion’s got going for it is the lighting,” says June. But she consents to be lowered into the healing fountain at Lourdes, as her three friends pray around her: the Catholic Gash, the Jewish Leah, and Joy, who chants. In the center of the ecumenical tableau, Veanne Cox looks out over the audience, wearing an expression of perfect serenity.

It’s one of the best moments of a very good performance. Ms. Cox doesn’t make June a victim. Her liver may be failing, but her spine is intact. Still, even she can’t solve Ms. Lavery’s proclivity for making her characters sound like writers. Like the psychologist and the grieving mother in “Frozen,” June finds it suspiciously easy to turn an elegant phrase. “Did I … not use all my white corpuscles in an efficient and military onslaught against the mighty C?” she wonders aloud.

June’s friends are not exactly revelations. Gash is a variation on the stock figure of the wisecracking, libido-riddled drag queen. With an actor less funny or less assured than the terrific Jeffrey Carlson, the play would sputter. The same goes for Leah, in the traditional figure of the ditzy American. Clea Lewis, so funny in Woody Allen’s last play at the Atlantic, once again proves that beneath her piping novelty voice lie real acting chops. As the raging, hard-drinking Joy, Florencia Lozano can’t save a tedious subplot about a dead lover.

Director Doug Hughes does his usual inventive work here. The action has been intricately carved: As Mr. Carlson and Ms. Lewis narrate the story, they sometimes re-enact the scenes they’re describing. Without losing the emotional stakes, Mr. Hughes lets a spirit of play pervade the show. Last year’s string of successes continues.

June breaks down, the plot winds up, and Ms. Lavery ventures onto some challenging moral and ethical ground. The play could have been written to emphasize all the knotty issues associated with mercy-killing, but for a comedy like this one, it probably would have been (so to speak) fatal. Still, it’s clear she has given the subject some thought.

Ms. Lavery has taken the unusual step of acknowledging, on the first page of the production script, the newspaper articles and real-life events that in formed her work. (Last month, the New York Times reported that Ms. Lavery has been accused of plagiarizing aspects of “Frozen”; this note looks like a ritual rolling up of her sleeves, proving there’s nothing to hide.) With this information in hand, we can interpret the last few scenes as a strong, implicit statement of her view. It may not convince, but it does entertain.