Elena tells Stefan that while Katherine is gone, she still doesn't feel safe and can't be with him right now.
She compels Matt to pick a fight with Tyler, intending for Tyler to kill him.
Just as the characters—and the audience—think the danger has passed, the episode ends on a massive cliffhanger:
As Elena walks to her car in the parking lot, she is suddenly abducted by a masked figure , setting the stage for the introduction of the "Original" vampires. The Vampire Diaries recap: Teen Wolf Too
Katherine reveals she has a witch of her own, Lucy Bennett (Bonnie's cousin), who has magically linked Katherine to Elena. This means any physical harm inflicted on Katherine—like being staked—is simultaneously felt by Elena.