Marguerite Caine's physicist parents are known for their radical scientific achievements. Their most astonishing invention: the Firebird, which allows users to jump into parallel universes, some vastly altered from our own. But when Marguerite?s father is murdered, the killer?her parent?s handsome and enigmatic assistant Paul?escapes into another dimension before the law can touch him. Marguerite can?t let the man who destroyed her family go free, and she races after Paul through different universes, where their lives entangle in increasingly familiar ways. With each encounter she begins to question Paul?s guilt?and her own heart. Soon she discovers a reality where we witness the countless other lives we might lead in an amazingly intricate multiverse, and ask whether, amid infinite possibilities, one love can endure.