Now, years after Lucia, Hanon, Rina, Caren, Noel, Coco, and Seira's story in Pure ended, Sara is revived and the daughters of the mermaids of Pichi Pichi Pitch are learning of the secrets their mothers' families hold. As they discover their mermaids, a new threat approaches. Will their mothers be able to teach them how to fight? Or will some roles as Mermaid Princesses be decined? And who is this new threat just on the horizon...