- That the Original Witch was actually Klaus and Rebekah's mother. She was faced with an impossible task after one of her son was bitten by a werewolf: turn the rest of her family into vampires so they could fight back. She did so.
- But Rebekah said her father - Mikael! - then discovered that his wife had an affair with a werewolf and that Klaus was not his son. He killed his wife, and the family all separated from there, except Elijah, Rebekah and Klaus, who made a pact to stick together.
- That is why Rebekah is so afraid of Mikael being woken up... HOWEVER, Elena, with the help of Bonnie and Alaric, then interpreted the cave drawings and learned the truth: Klaus killed his mother! He blamed it on his father so he could have company for the rest of his life, but he was actually angry at his mom for placing a hybrid curse on him and making him the only one of his kind.
- When Rebekah accepts this truth, she breaks down crying.
Meanwhile, Damon breaks Stefan out of his dungeon and they have a night on the town. But Mikael arrives and threatens to kill Damon if Stefan doesn't tell him where Klaus is. Stefan says he can get Klaus to come to Mystic Falls. Mikael says: you better.
- Stefan then tells his brother that, yes, he wants Klaus dead so he can be free. But only so he can be free to leave. He's sick of acting all nice.
Source: TV Fanatic