TV Edge reported on recent comments made by the executive producer of the series, Andrew Miller. He admitted that the feelings between the two won't be "on the backburner" for much longer. In fact, Thomas Dekker also recently revealed that the episode where Adam gives in to his feelings has already been filmed. No word on when it will air though.
When the series returns on January, the circle will have to deal with the fact Cassie has dark magic inside her because she is a descendant of the Balcoin blood line of witches. She isn't the only one though. There is another in the circle from the same blood line, but it hasn't been revealed who that is yet. The Balcoin blood flowing through her veins will change Cassie once she experiments more with her powers.