In the year 2019, a plague has transformed almost every human into a vampire. Faced with a dwindling blood supply, the fractured dominant race plots their survival; meanwhile, a researcher works with a covert band of vampires on a way to save humankind.

This season, Katherine's appearance in Mystic Falls will throw a wrench into the love triangle between Stefan, Elena and Damon, and the other residents of Mystic Falls must choose sides as they fall victim to a new breed of danger. New and unexpected friendships will be forged, allies will become enemies and hearts will be broken. Plus, Stefan and Damon will be forced to face a villain more evil and diabolical than they thought possible.

Life hasn't been the same for Elena since the tragic death of her parents, but she tries to pick up the pieces and provide support for her troubled younger brother, Jeremy. On her first day back at Mystic Falls High School, Elena meets the mysterious new guy, Stefan, and the two seeming lost souls form an instant connection. What Elena doesn't know, however, is that Stefan is a vampire, constantly resisting the urge to taste her blood. But Stefan, it seems, has a greater evil to deal with when his dangerous older brother, Damon, shows up to wreak havoc on the town of Mystic Falls — and claim Elena for himself.

Season three opens the door to learn more about Klaus and the Original Family as his motives for wanting Stefan on his side are finally revealed. As Stefan sinks deeper into the dark side, Damon and Elena struggle with the guilt of their growing bond, even as they work together to bring Stefan back from the edge.

As the war between the vampires and the Lycans rages on, Selene, a former member of the Death Dealers (an elite vampire special forces unit that hunts werewolves), and Michael, the werewolf hybrid, work together in an effort to unlock the secrets of their respective bloodlines.

Vampires and werewolves have waged a nocturnal war against each other for centuries. But all bets are off when a female vampire warrior named Selene, who's famous for her strength and werewolf-hunting prowess, becomes smitten with a peace-loving male werewolf, Michael, who wants to end the war.

Having escaped years of imprisonment, vampire warrioress Selene finds herself in a changed world where humans have discovered the existence of both Vampire and Lycan clans and are conducting an all-out war to eradicate both immortal species. Now Selene must battle the humans and a frightening new breed of super Lycans to ensure the death dealers' survival.