Caroline knows no more humanity after her mother Sheriff Forbes succumbed to cancer. In the upcoming episode of "The Vampire Diaries" titled "The Downward Spiral," viewers will see a sinister Caroline who thinks that Stefan does not have romantic feelings for her. 

Stefan finds a way to bring things back to normal as Caroline provides her friends with "an unexpected ultimatum." But his interference only triggers "a chain of dangerous events" and he, along with Elena, has to "race against the clock" so as to prevent the troubles at hand from evolving and multiplying. 

Also in the upcoming episode, as Damon tries to know more about the prison world, he learns of a "devastating" truth about his mother, whom he thinks died long ago. The new episode suggests that Lily Salvatore may still be alive but it will be heartbreaking to know that she is trapped in another prison world. 

Meanwhile, through the course of Enzo's mission to bring as many evils to Sara Salvatore as he can, he soon realizes that he is slowly becoming "increasingly intrigued" by her. 

Lastly, the upcoming episode also follows Bonnie who, after coming back from the prison of the past, is having a hard time adjusting now that she is back in the present and real world. 

"With Bonnie's return, with Caroline switching off her humanity, with the mother reveal, it really does launch us into the next and final chapter of the season, which is leading us in some very clear directions," executive producer Julie Plec told The Hollywood Reporter. 

Episode 16 will also be Ian Somerhalder's first dip into the directorial scene.

"It was the coolest environment to learn in, and thank you Warner Bros for the couple million bucks to spend really creating an incredible 42 minutes of television. It was my favorite professional experience ever," the actor said during the Wizard World's Cleveland Comic Con event. 

"The Vampire Diaries" season 6 episode 16, "The Downward Spiral," will air on March 12.