What is the vampire diaries season 1 episode 13?

The Vampire Diaries Season 1 Episode 13 is titled "Children of the Damned".

In this episode, Stefan and Damon continue to struggle with their strained relationship while Elena and some of her classmates are taken hostage by a group of vampires, who call themselves "The Children of the Damned". The vampires reveal that they were turned by Katherine Pierce over 140 years ago and have been hunting for her ever since.

Meanwhile, Bonnie's powers are growing stronger and she helps Jeremy communicate with his dead ex-girlfriend. Caroline and Matt's relationship also takes a turn as Caroline reveals her true nature as a vampire.

The episode ends with a major revelation - Katherine is back in town and has been impersonating Elena, causing chaos and confusion amongst the main characters.