The fate of the multiverse rests in Marguerite's hands in the final installment of the Firebird trilogy by New York Times bestselling author Claudia Gray. Ever since she used the Firebird, her parent's invention, to cross through alternate dimensions, Marguerite has been at the center of a cross-dimensional feud. Now she has learned that the evil Triad Corporation plans to destroy hundreds of universes, using their ultimate weapon: another dimension's Marguerite who is wicked, psychologically twisted, and always one step ahead.