Separated At Birth

On August 31st, twins were born to a mermaid and a werewolf. But a vengeance seeking vampire plots to take the children, who are most powerful together, so the werewolf and the mermaid separate their children and put them in the human world where they are both adopted. Now 16 years later, they meet again and discover that they are twins. How will they get home to save their parents?

First Version on Quotev @YourHappyEnding