It began with two sisters, Shannon and Isobel Blackwell. Both have been turned into monsters as curses done to them by Witches. Isobel is a Vampire turned in 1888 when science and magic collide. She's turned and develops a hunger for blood and begins a killing spree. The Ashford witches of Beacon Hallows can't allow this but aren't strong enough to stop her and make an offer to Isobel's sister Shannon, who is indirectly responsible for her sisters state. They offer her the power and time to stop her. They turn her into a Werewolf.
The two sisters chase each other for decades and Shannon eventually catches up to Isobel. They fight, and Shannon even gets the upper hand on her sister, but can't deliver the killing blow. Instead, she decides to lock her sister away in the Beacon Hallows Mines for all eternity. This angers the witches who curse Shannon with immortality, to be her sister's warden forever.
TODAY. Isobel finally manages to escape being locked up after some kids stumble onto her tomb. Shannon is summoned back to Beacon Hallows, and the siblings battle resumes, with a new generation of friends at Shannon's side. Isobel launches a plan of revenge on the descendants of the witches who cursed her, but times have changed and the humans of Beacon Hallows may be more prepared to deal with Supernatural threats than their previous generations.