Fifteen-year-old Marisol is the daughter of a soucouyant. Every new moon, she sheds her skin like the many women before her, shifting into a fireball witch who must fly into the night and slowly sip from the lives of others to sustain her own. But Brooklyn is no place for fireball witches with all its bright lights, shut windows, and bolt-locked doors. While Marisol hoped they would leave their old traditions behind when they emigrated from the islands, she knows this will never happen while she remains ensnared by the one person who keeps her chained to her magical past, her mother. Seventeen-year-old Genevieve is the daughter of a college professor and a newly minted older half sister of twins. Her worsening skin condition and the babies' constant wailing keep her up at night, when she stares at the dark sky with a deep longing to inhale it all. She hopes to quench the hunger that gnaws at her, one that seems to reach for some memory of her estranged mother. When a new nanny arrives to help with the twins, a family secret connecting her to Marisol is revealed, and Gen begins to find answers to questions she hasn't even thought to ask. But the girls soon discover that the very skin keeping their flames locked beneath the surface may be more explosive to the relationships around them than any ancient magic.