Solstice: Fated souls

The year is 2022. Rosemary & Davian currently appear to be 16 years old and just finished their sophomore year of High school. Back in 2006, Renesmee Cullen was born. After the confrontation with the Volturi, the whole family was able to move on with their lives in peace. Eventually, 7 years later Renesmee & Jacob got married and a year later, the twins were born. 3/4 human and 1/4 vampire until the shapeshifting gene is activated, they are different from the rest, with the greatest potential. Although the Volturi never intervened again, the twins' birth intrigued them and they asked to see them once every year to study their development. That was the start of a new tradition for the family; every year a "summer vacation" was made to Italy to visit the Volturi. Five years after the twins were born, came their little sister Giselle. However, this year the usual summer visit changes everything. Because the twins are now also shapeshifters, and there's a certain vampire guard who will be implicated as a soulmate. Will he deny the gift fate has bestowed on him, or will he embrace it and in the process change vampire history as known?