Amid a global environmental catastrophe, a strained bond between two sisters threatens to snap along the hairlines of societal fracture.

On the second-worst day of Rachel’s life, she wakes up to the end of the world. At least, that’s what it looks like outside. Her yard, just like the rest of the globe, is covered in a mysterious ash-like substance. And yet, Rachel can’t summon the rest of the world’s panic, as she is still reeling from the devastating diagnosis her youngest daughter received yesterday. To her, the world has already ended.

And yet, for her sister, Meg, it’s the opposite; she has no choice but to panic. She’s nearing the end of her first pregnancy, so she is gripped by the ash and what it means for the future of humanity. Glued to the news and the online chatter, she’s among the first to hear the rumors: The ash may be healing, but using it will create an environmental catastrophe that will affect all of them.

As society wades through rumors and lies, speculation and mistrust, a clear line is drawn between sides. Driven by their own deepest fears, Rachel and Meg find themselves on opposite sides of the divide, where the only thing holding them together is their mutual love for Rachel’s daughter, Scout. But when Scout’s fate rests on using the ash, the sisters—like the rest of society—must ask themselves: In a world so divided, is there anything we can all fight for?