Okay, so, this is what I wanted out of the last episode. Ugh. This was so good.
Katherine stumbles out of the woods and into on coming traffic. A kind passerby takes pity on her, but soon realizes who she is and maces her. Then she calls someone to get her. However, Matt and Jermey come out of the woods after her and take her with them.
They end up stopping for gas (while she complains constantly about being sick- welcome to humanity) and letting her go the bathroom, which fine. But no one bothers to check to make sure she's actually staying in the bathroom. The clerk, realizing she's Katherine and Silas wants her, points her out so Matt is able to grab her before she flees. Eventually, they end up at a camp site that Jeremy and Elena used to frequent.
Speaking of Elena, she runs into Silas (looking like Stefan) and he gets into her head about all the shit that's going on at home that Damon has 'caused.' Silas then gets a call telling him Katherine was spotted and he bails. Elena then goes to find Damon where she attempts to seduce him, which really ends up just being a way to try to kill him. Damon tries to get her out of her rage, and she ends up stabbing herself through the leg to calm down. When she chats with Damon about her feelings for Stefan, she finally breaks through the rage.
During this, Caroline and Elena realize that the microbiology professor on campus is the same person who signed off on their roommate's death being ruled a suicide. They suspect they've got their own version of the counsel here on college. So, they try to get into his inner circle by taking his class, but they are promptly kicked out. However, one of the other students seems to take a liking to Caroline and tells Elena that the professor is involved in some sort of secret society. I'm not sure why, but I'm totally suspicious of him.
Eventually, Silas finds Matt in the woods. He tells him not to scream, but his mind control doesn't work on him, so he yells for Jeremy to run. He and Katherine take off, while Silas figures out that The Travelers are already in Matt's head and are watching him through him. (You know what I mean). He kills Matt and wanders around looking for Jeremy and Katherine.
When Jeremy realizes Matt is missing, he goes back to look for him. Katherine calls him an idiot and he informs her that this is why everyone hates her. When he gets back, he starts a fight with Silas and when he's about to 'win', Silas reminds him that he's immortal and stabs through himself to reach Jeremy. Katherine shows up and shoots Silas a bunch of times.
While Matt is dead, he runs into Bonnie on the other side. She tells him the truth, but realizes that once he's back allive, he won't remember it. He does (I think) encourage Bonnie to tell the others the truth.
And the end of the episode, Damon and Elena are back in Mystic Falls. Liz has found the safe that they suspect Stefan is in. However, when they open it, it's not Stefan. It's just a guy who has been eaten by a vampire. I don't think we know at this point if Stefan has actually turned off his humanity, but I think we're suggesting that he has.