Once Bonnie is gone, Damon smacks Mason awake. Out in the foyer, Bonnie runs into Caroline. She asks about Liz, but is still obviously uncomfortable. Caroline gives her every chance, and finally Bonnie tells her that she knows the moonstone is in the old well they used to play near at the outskirts of the old Lockwood estate ruins, when they were kids. She then texts the information to Stefan and tells Caroline that she's leaving. Caroline is patient but vulnerable here, and ultimately, Bonnie cannot keep up her wall. She asks her old friend if she'll accompany her on her moonstone quest.

Lockwood Mansion: Matt tries to feel Elena out for information about Caroline and whether she's seeing anyone. Stefan joins them at the sorting table, but doesn't speak to either of them. When Tyler comes in looking for Mason, Stefan tells him he took off for a while. Stefan then receives Bonnie's text about the well and speeds out the door. Matt notices the tension, but says he won't ask about it. Elena, being the world's worst faker, promptly follows Stefan outside.

She catches up to Stefan at the well. It drives Elena nutty not to know what's going on, and she's veering dangerously close to human-Caroline-levels of neediness here, although it's not that she's insecure about Stefan's love. She just has to know everything. Immediately. Stefan catches her up on the moonstone sitch, and then rips off the lock and cover that's sealing the well. After a quick look down the well with aid of a flashlight, Stefan plops down into it and immediately starts to smolder. The well is full of vervain stew. Stefan grunts, growls, cries and finally ekes out, "Vervain. Help. Help!" Commercial

Elena tries to lift the chain from the ground, but it's magically rusted in a way that makes it extra heavy, like magical rust does. Fortunately for her, Caroline hears her cries and Stealth-Salvatores right up to the well, and to Stefan's rescue.

Mossy Manse: I have to tell you about this part really quickly and clinically, because I don't want to spend the next five years hating my Evil Pixie Monster when what he so clearly needs is love. Jeremy gives Damon some wolfsbane (which is to werewolves what vervain is to vampires), so he shoves it in Brick House's luscious lips, which makes him vomit or gag or otherwise leak and spew yucky stuff from his lips. Maybe it's purging the Katherine cooties from him? Yeah, let's think that. And I'm going to skip ahead to a later scene because this all makes me very tense. When the wolfsbane doesn't get Damon much useful intel on Katherine's nefarious scheme, he heats up a poker in the fire and tortures Mason, and yet he doesn't remove the shirt -- his or Mason's -- I'm not fussy. He just asks what Katherine is up to. Katherine, Katherine, Katherine. Bah. What about me, Damon? What about my needs? Perhaps if you'd give him a mud bath, you'd get what you want. I know I would. Damon laughs at me or possibly at Mason's story: Katherine and he are in love, and she wants the moonstone to free him from his curse. He laughs bitterly, because he was Mason for so very long. Eventually, he realizes he has to kill him. Mason seems almost relieved by this. He asks Jeremy to look out for Tyler, and you can see Jeremy wibble. I go deep into denial and tell myself Damon will have a change of heart or Germ will talk Damon out of what's to come. Damon can't reach me directly, so he settles on throttling Jeremy, because it's not The Vampire Diaries without a good throttling, and tells him if he wants to play with the big boys, he's got to learn it's kill or be killed (and hey, that was last week's title), so he'd better suck it up or leave. No comment. Mason's time on our show ends with him writhing in pain, still fully clothed, mouth dripping with exorcised Katherine cooties and DAMON RIPPING THE HEART OUT OF MASON'S CHEST AND TOSSING IT ACROSS THE ROOM. Damon, I am going to hate you with all my might, for many, many minutes to come.