As the tile of the episode would suggest, the circle members are seeking the person working with the witch hunters. On the other hand, maybe more than one person could be considered a traitor if you look at Charles and Dawn’s points of view.

Here is the synopsis straight from the CW:

THE CIRCLE DOES MAGIC TO FIND THE REMAINING CRYSTALS — When a crystal is magically stolen from the abandoned house, the Circle decides it was the traitor witch working with Eben (guest star Sammi Rotibi) so Jake (Chris Zylka) calls for a meeting with Isaac (guest star JR Bourne) to see if they can get him to change sides. Cassie’s (Britt Robertson) loose grasp on her dark magic threatens to destroy any possible alliance when their pursuit of the traitor leads them to the “Creepiest Place on Earth.” Meanwhile, Faye (Phoebe Tonkin) and Jake (Chris Zylka) work together to steal Dawn’s (Natasha Henstridge) crystal, Melissa (Jessica Parker Kennedy) and Adam (Thomas Dekker) pair up and uncover a new magic trick. Meanwhile, a frustrated Diana (Shelley Hennig) reaches out to Charles (Gale Harold) for help. Eagle Egilsson directed the episode written by Roger Grant & Katie Wech (#120).

In case you missed it earlier today, the CW also just released the photos for the previous episode called Crystal.

As a quick recap, the final episodes are as follows:
19: Crystal April 19
20: Traitor April 26
21: Prom May 3
22: Family May 10

How do you think Dawn is going to take it when she realizes Faye’s betrayal?