1864; Quarry: Newbie Vamp-Stefan brings a young woman to Tadpole-Damon, who hasn't fed because that was the deal, Stefan. Stefan tells Damon what happened with their father and how the blood was too strong for him to resist. He then tempts big brother by enumerating his new powers and abilities, which include the ability to turn off any inconvenient emotion. "Like a switch." Now, is that an anachronism? Whatever. His point is he can even turn off the horrible pain of living in a Katherine-less world. Ugh. And the bottom line is, Stefan won't let his brother die. "We can do this -- together." When Stefan's words don't move Damon, he knows just what will. He bites into the woman's neck -- sort of like sticking the straw in the juice box for your kid. Transitioning Damon cannot resist the fresh blood, and the rest is history.
2010; Mossy Manse Parlor: Damon: "From the moment Stefan had his first taste of human blood, he was a different person. I suppose I should thank him. It's been a Hell of a ride." Realization spreads over Elena's face. "Oh my God. He said he wanted to die. That's why he won't feed." Damon shrugs. "His choice, if he's stupid enough to make it, so be it." Elena tells him not to pretend he doesn't care and rushes off toward the dungeon.
Gilbert Gables; Jeremy's Bed: He wakes to find Anna lying with him. You can tell she wants to tell him about her mother, but he looks so adorable, she just caresses his face. As Jeremy drifts back to sleep, Anna says: "Goodbye" and leaves through the window. Goodbye? Does she intend to go with Pearl, or does she just intend to tell Pearl she's made up her mind? Eek. Poor Germ. He's quite unstable. You can't leave him, Anna, not without explaining your situation, at least.
2010; Quarry: Stefan has returned to the scene of the crime and it's flashback-y, but I'm gonna sum up. He remembers a newly transitioned Damon who is enjoying his new power, but so very much hating on his brother. "You got what you wanted --- you and me for all eternity. But here it is, brother. I will make it an eternity of misery for you." So far, so good. Next, Emily Bennett finds Stefan. She can tell he has completed his transformation. She helped him, because Katherine once saved her life, and Emily owed her, but she was hoping that Stefan would choose not to turn; she wouldn't wish Katherine's curse (vampirism, I presume) on anyone. When Stefan says it feels more like a gift than a curse, Emily tells him that will change, "Because even in death, your heart is pure, Stefan. I sense that about you. That will be your curse." As he calls out to her, the flashback ends. If Stefan's curse is purity of heart, what's Damon's -- love?