Set about four years after breaking dawn, Renesmee is taken by the volturi because Aro wants her gift,. with also in hopes of luring his other gifts, Bella, Edward, and Alice. He is still after the power that his greed drives him to have. With that being said, with precious Renesmee in the picture, Jane has grown incredibly jealous and hopes to be rid of her, and will in a way be betraying Aro, so Jane will remain his one and only precious gift. The Cullens, Jacob, and the wolves plan to do whatever it take to get Renesmee back, they plan to bring back some of their gifted vampire friends along with another who the volturi doesn't know exists, they hope to use this person, to infiltrate and gain the trust of Aro and the volturi and bring Renesmee back in the safety of their arms. But in end, the last person they expected, decides to help them.