Between partying, drinking, and avoiding anything and, well, everyone, former ballerina Laure has no time to be anything but a monster, a vessel for Acheron. When Laure stumbles across a mysterious dead body during one of her nights out, she's forced to notice the cracks stretching beyond herself -- that below the streets of Paris, Elysium is dying, and Acheron and Lethe's influence is spilling into the streets like a blight. Laure isn't the only of Elysium's beasts to rise from the ruins of Palais Garnier, and someone is mobilizing an army of monsters with plans greater than Laure, Andor, and Keturah could have ever guessed. While Laure is warring between her wants and Acheron's ever-demanding appetite, she and her circle of monsters are left to reckon with a not-so-simple question: how do you save yourself from oblivion?