Olivia Beckett has lived through thousands of lifetimes, dispatching miscreant supernatural creatures alongside her sisters as the mythological trio of Furies. Memories of her past lives begin to appear and haunt her, and she starts questioning everything she thought she knew about her life and her duty. In the midst of a brewing war between the factions of Creatures, Olivia goes against all the rules and falls in love with a human, only to realize he may be connected to her mysterious past. Can she have it all, or will she have to make the ultimate sacrifice in order to stop the war?