In 1864, Stefan and Katherine dance at the Lockwood mansion. He spots Elena going off with Damon and runs after him, suddenly popping back up in the present. Katherine is there and tells him to love her again. Suddenly, he wakes up with Elena in his arms. Snapping out of it, he leaps back and realizes it's Katherine. "I could rip you to shreds and do my nails at the same time," she quips. They sit around and she flips through his diary, sips blood and they chat about werewolves. They remember the Lockwood ball. The Lockwoods were the werewolves that chased the vampires out. She accuses him of returning just to fall in love with her again. As they kiss, he stakes her in the back then drags her to the basement and enchains her. He demands to know why she is back. She tells him more about the founder's ball and how she confronted George about their supernatural secrets. Then she recalls Stefan telling her how much he loved her. "I never compelled your love," she tells him. He tells her that his feelings for her have all turned to hate. She shrugs and admits that she sold out her friends and family, allowing the town's people to burn all the vampires out. She recalls how his father poisoned his blood and the attempt to rescue her went wrong so that he and his brother got killed. "You died for love," she says. They taunt each other and she threatens him until he attacks her. She kicks him off.
Damon informs Elena that he's going to the Lockwood barbecue to put some silver in Mason. Meanwhile, at the Lockwood mansion, Mason assures Tyler that things will be okay. They mention the moonstone. Tyler caresses it as Mason leaves. He goes to see Jenna, Elena and Alaric. As they do shots, Damon shows up. Elena goes out and calls Stefan, worrying. Caroline comes out and babbles. They get together and play pictionary. Damon digs around in the kitchen for some silver. After dinner, and lots of barbs between the men, Mason corners Damon and tells him to stop playing games. He asks if they can both be above the old fight. After they shake on it, they leave. Damon follows him home and stabs him with the silver. It doesn't do much except make him a new enemy. Annoyed, Mason goes into his house and Tyler starts demanding to know how the curse is triggered. Mason admits that you have to kill someone.
Caroline and Elena drive off. The blond teases her about her love life and then the tire pops. They wait until night falls and continue bickering about doomed vampire-human love. As the tow truck drives up, Caroline begs her not to go. Elena heads to Stefan's. As she walks into the house, Katherine approaches her. They look each other over. Stefan rushes in and Katherine vanishes. Katherine goes to see Caroline and threatens to kill her again if she doesn't end things between Stefan and Elena. Caroline goes back to the bar and Elena shows up to tell her that all the stuff she was saying was right. Elena returns to Stefan and he worries about Katherine. She refuses to back away because of her. He admits that Katherine is already between them. They later meet up and make up before worrying about Katherine. He tells her that the other woman is incapable of love.
Damon runs into Katherine on the street. They talk about killing werewolves. She recalls giving George a moonstone before he helped her fake her death. Before she left, she rushed to Stefan and promised him that they would be together again.
Cryptic commentary: That was a pretty trippy episode with all of the leaping back and forth in time. Lots of information packed in and Katherine didn't pull any punches about what she's up to. I think we should place bets on how long it takes Tyler to kill someone.