The producer revealed that Stefan's (Paul Wesley) behaviour will lead Damon (Ian Somerhalder) to reconsider acting on his desire for Elena (Nina Dobrev).
"When the show returns, Stefan has been MIA since he stole Klaus's family coffins, but we'll learn he's been busy trying to figure out a way to stay one step ahead of Klaus," Plec told TV Line.
She continued: "When Elena and Damon finally have the opportunity to confront him about his recent actions, his response makes Damon think twice about acting on his feelings for Elena."
Joseph Morgan, who plays Klaus, recently revealed that he'd like to see a fight between the hybrid vampire and his half-brother Elijah (Daniel Gillies).
Robert Ri'chard will appear as a love interest for Bonnie (Katerina Graham) on The Vampire Diaries.
The Vampire Diaries returns with new episodes on January 5 on The CW.