It’s the day after tomorrow, and New York City has been cut off from the rest of the world by a biological-weapon attack followed by the invasion of the white-helmeted Eggheads, an army of Islamist lunatics who may or may not be in league with the Chinese, shadowy corporate interests, or Mrs. Winship’s Farm, a rural utopian community of white supremacists. Surviving women are given Auschwitz-style tattoos on the back of the neck and required to cover their heads with identifying blue bonnets when in public or be hanged in Union Square; surviving men—and there are not many—are castrated and worse. Nobody really quite knows what is going on in the rest of the world, but there are rumors of safe havens in Pennsylvania and Ohio.

Such is the world of Through the Yellow Hour, the writer and director Adam Rapp’s claustrophobic new play at the Rattlestick Playwrights Theater downtown. I am an admirer of these kinds of audacious attempts at large-scale storytelling without a War Horsebudget or extranaturalistic pretentiousness. There is a fine-grained and sometimes uncomfortable realism at work in the play: When the first gun goes off, blood splatters the walls. There is a great deal of physical trauma and medical unpleasantness in the story, as Ellen (Hani Furstenberg), a nurse dug in to her fortified Manhattan apartment, fends off invaders, barters drugs and other supplies, and hopes for news of her vanished husband, who almost certainly has been taken prisoner by the Eggheads.