This episode was all about Vicki.
The new vampire craved blood, but Stefan tried to teach her how to control her cravings and feast only on animals. Damon, of course, was willing to show Vicki some new tricks, which included how to move quicky. This backfired, though, when she darted away from her brothers.
Vicki ended up home with Matt, resisting the urge to drink his blood. She texted Jeremy and said she wanted to meet him at the school's Halloween party. She showed up, aptly dressed as a vampire.
Damon, meanwhile, was eavesdropping on a conversation at the bar. He overheard the Strattons talking about vampires and vervane and swopped in to flirt with Mrs. Stratton after her husband left. Damon gleaned some information from her and learned that the Founder's Counsel is definitely aware that vampires have returned to town. The most interesting part of this conversation?
Damon was unable to glamor Mrs. Stratton, despite his best efforts.
Also, in the most boring storyline from the episode, Bonnie learned more about her witch heritage from her grandmother. The necklace Damon had given to Caroline, for example, had belonged to Bonnie's great, great grandmother.
Back to the party: as Vicki made out with Jeremy, she cut his lip and started to slurp his blood. When Elena tried to intervene, Vicki was on the verge of gouging her neck WHEN STEFAN CAME IN AND DROVE A WOODEN STAKE THROUGH VICKI'S HEART! RIP, Vicks.
Jeremy, of course, was a mess from what he witnessed. Elena told Stefan to make him forget, but Stefan wasn't sure if he could, due to his lack of power. Damon - perhaps feeling guilty from an earlier conversation with Elena, as the pair stood over Vicki's body - offered his services. He hypnotized Jeremy to believe that Vicki simply ran away.
At the end of the hour, Elena said she wished she could forget everything, but that wasn't possible now. Her feelings for Stefan meant too much to her.