Makers of The Vampire Diaries had a difficult task to get things back on track after killing off the popular if evil Katherine (Nina Dobrev). And how did they do it? But giving their viewers plenty of Elena (also Nina Dobrev).
As viewers of the show will know, Elena has been infected with a mysterious virus that makes her crave vampire blood and hallucinate. In this episode though, her main desire seemed to be to find Damon (Ian Somerhalder), even if it involved stabbing Liv in the stomach to do so.
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It may have been the right decision, as after breaking Damon out of that basement, he gave her a bottle of Stefan's blood - which is especially considerate when you know that he is infected with the same virus.
This led to an elaborate search for Enzo and the antidote to the virus, which they found. With their memories restored, they could go back to being angry with each other (he did kill her good friend Aaron, after all).
And how did they show how angry they were? By having sex.
Further mysteries await...