A Volturi Guard and A Swan

Hannah Swan is Bella Swan's adopted older sister by 4 years. Hannah is close with the Cullen coven, she is closest with Esme and Rosalie. Esme is her mother figure because her adopted mom and her where never close and argued all the time. She and Rosalie are close because they have similar personalities. What happens when a newborn army comes to attack her younger sister? What happens when the strongest member of the Volturi guard saves her from getting raped by someone? What happens if they are mates.