In a bleak, post-apocalyptic Earth ruled by powerful machine intelligence, a teenage girl from Oakland is given super abilities and charged with saving the world.

Thirteen-year-old Josephine has always seen herself as a loner, not a hero. She survived the end of the world—and what came after—by talking to her twin's ghost in a secret language they call the Twinkling. Transformed into a biomechanical robot, she's been charged with protecting the Bay Area—now Yerba City—alongside an army of her clones called the Josephines.

But when Yerba City is threatened by a devastating language virus, the Twinkling is the only thing that stands between the last shreds of civilization and the Babble. There's just one problem—the head of Josephine One has been stolen, and it contains the language's secrets. In the wrong hands, the Twinkling could be used to take down the entire Josephine army before laying waste to what's left of...