Ten Days In Volterra:
The now reestablished storyline is that after Ness and Jake broke up (due to her losing their first child through a stabbing) Ness is determined to find out who killed her baby. She finds out its a member of the volturi. Then via a school trip she goes to italy and seduces alec while gaining friends and enemys there.
She ends up learning how to be a vampire from and falling for Alec. Then after being threatened by exposure for her true reasons for being there by Jane, she bargins to leave if she wont say a word. She ends up killing the person who wronged her before returning to forks to reignite her engagement to Jacob with no explanation for Alec leaving him heartbroken. They then go on to become good friends and keep intab through letters - much to everyones dismay. Alec, Demitry and Felix even attened Ness and Jakes wedding.
I then planned to do a flash forward to the future (after the enaged life book and another which would have included their children's bith and the following) where the volturi come to kill the culllens again do to the hybrid race created by ness and jake through their ten children. Alec ends up being killed by the volturi as he defends Renesmee and his last words are renesmees name equaling in Renesmee being emotionally scarred and forever feeling guilty.
After this i planned to write a final book about the Cullen's taking over the volturi. In my mind Ness and Jake along with their children would have asablished a monarchy, they would hve a kindom built for supernatural creatures on a island. They would rule over all supernatural kinds: witches, vampires, werewolves and shapeshifters (would have gotten more into why they rule over all in the book (basically Ness' paternal grandmother was a witch)) and eventually would have opened themselves up to the world revealing that all existes.