Last dragon or not (how to train your dragon 3)

one day there was a girl named sumoona and her sister starnight. Sumoona was the youngest of her clan and very different she had curly brown hair and green eyes. But no matter how different her parents loved her libe was good except everyone calling her weird runt. starnight was nice and cared for her little sister more than anything. one day starnight went deep in rhe icey cave with sumoona they found a glowing stone in the ice she careful pulled it out and discovered it's power. knowing it let's you talk to dragons! starnight made it into a necklace and gave it to sumoona has a gift that will lead her though life. until one day during a clan war her parents died. Her sister turned aganist her everything she knew and love are gone. Her sister teamed up with the other clan and gave away all there secret away The other clan. soon the clan was defeated and had to find a new island. they sailed into a storm...
will they survive?