Elena is captured by Dr Wes Maxfield in Whitmore House after being vervained and locked in the cell next to Damon.
Aaron learns that Elena is a Vampire.
We learn that Enzo didn't die in the 1958 New Year's fire, then introduces himself to Elena by his number 12144.
Elena learns that her father Grayson Gilbert, Mystic Falls town doctor was a Augustine doctor who worked with Dr Maxfield on Vampire experiments.
Stefan tries to encourage Katherine to write down her feelings and thoughts in a diary, which she does not enjoy.
Caroline attempts to help Stefan with his PTSD by locking him in a safe. Katherine helps Stefan while he was in the box, by making him realize that he was so focused on the break up that he wasn't concerned about the physical pain with dying over and over again during the summer.
It is revealed that Aaron is a member of the Whitmore family.
Katherine and Stefan kissed.
It is revealed that Damon was sold out to Dr Whitmore by his own descendant Joseph Salvatore who also had intended to do the same to Stefan.
This betrayal is what eventually lead Joseph to his death by Damon.
Damon reveals that he never told Stefan about being imprisoned and tortured by the Augustine society because he didn't want him to have anything else to feel guilty about.
It is revealed that Damon is responsible for the death of Aaron's parents.
Damon reveals that as revenge against the Whitmore family, he would kill one generation while living one alive to grow up and have children, and then repeat the cycle all over again.
Damon also reveals that the last time he killed a Whitmore was a few months ago when Elena and he were together, her name was Sarah Whitmore, Aaron's aunt.