Sera has always felt as if she didn’t belong among her people, the Cerulean. She is curious about everything and can’t stop questioning her three mothers, her best friend, Leela, and even the High Priestess. Sera has longed for the day when the tether that connects her City Above the Sky to the earthly world below finally severs and sends the Cerulean to a new planet. But when Sera is chosen as the sacrifice to break the tether, she doesn’t know what to feel. To save her City, Sera must throw herself from its edge and end her own life. But something goes wrong and she survives the fall, landing in a place called Kaolin. She has heard tales about the humans there, and soon learns that the dangers her mothers warned her of are real. If Sera has any hope to return to her City, she’ll have to find the magic within herself to survive.

Sera has finally recognized the true power of her Cerulean blood. But in order to return home, she’ll need help from Agnes, Leo, and their grandmother—the only person with knowledge about the mysterious island of Braxos, where the Cerulean tether is anchored. Though the journey will be treacherous, Sera will risk anything to see her City again. Meanwhile, the High Priestess’s power has reached new heights in the City Above the Sky. And when Leela begins having visions of Sera, alive, she knows she’s the key to saving the City. But to bring Sera home, Leela must channel the strength, courage, and curiosity that once got her friend exiled. With the help of friends, family, and Cerulean magic, Leela and Sera could soon return to their normal lives. But when that time comes, will Leela be able to serve her City as blindly as she once did? And will Sera be able to leave everything and everyone she’s grown to love on the planet behind?