Britt Robertson, Thomas Dekker, Shelley Hennig Britt Robertson, Thomas Dekker, Shelley Hennig

The Secret Circle's coven is about to get even more complicated.

With the arrival of Cassie (Britt Robertson) in Chance Harbor, Diana (Shelley Hennig) and Adam's relationship is being called into question. (After all, Cassie and Adam's future is written in the stars.)

The Secret Circle takes a dark turn as the coven faces a new threat

As Cassie and Adam grow closer, we'll begin to discover the history between Adam (Thomas Dekker) and Diana, and "what works about them and what's not working about them," Dekker says.  "Diana is starting to lose faith in what we're about."

One person who's happy to see the usually strong couple going through trouble? Faye (Phoebe Tonkin), who is sick of playing second fiddle to Diana, the current leader of the coven.  "The thought that maybe Diana could get dumped is a little exciting for Faye," Tonkin says.

Meet The Secret Circle's Secret Coven

Get more scoop on the state of Adam and Diana's relationship straight from the cast:

The Secret Circle airs Thursdays at 9/8c on The CW.