Ten years ago, eight-year-old Nell Wick was sent alone to the Cradle, a sealed structure built beneath the surface of a war-torn world. Her parents spent every last cent on one passage, trading their own survival for hers. But her childhood was far darker than the nuclear clouds above. Surviving in the Shallows—the coldest, darkest level, where the city’s source of power is rationed by the hour—Nell trades machine repair for scraps of food.
When her engineering skills earn her a rare seat at the Academy, she’s handed a contest that could change everything: complete the lost scientific work of Coldlight’s inventor, Dr. Casimir Voss, and earn her place on the Floor, where the most affluent families are drowning in warmth and light.
Forced to partner with her class rival, they follow a manuscript of strange poems to hidden pages of Voss’s journal—and the spark between them burns hotter than anything in their laboratory. Through Voss’s words, Nell learns that Coldlight isn’t made by any machine at all.
As the lights fail level by level, Nell uncovers the truth the Bureau has buried since the Cradle first sank.
If she can’t unravel the secrets of an ancient magic lost to time, the city built to save humanity will become its watery tomb. To keep the lights on, she’ll have to decide how much of herself she’s willing to give—even if the man she’s falling for would rather let forty thousand passengers perish just to save her.
