Into The Depths

Elizabeth's life is normal, she has a close bond with her siblings but not so much her parents. It's her brother's birthday and she gets a gift from hell itself. While at her brother's party her sister is taken and she finds out what her family really is. She is human but they aren't. Will this keep her from saving her sister? Also if she can find her sister will she ever be forgiven by her family for letting her little sis get kidnapped?