Cassie and Diana discover secrets about their fathers and the last crystal piece, Jake and Melissa have very different reactions to the news that Nick is alive, and Eben returns....
Cassie discovered that Blackwell not only got her mom and Diana's mom pregnant, but he also used magic to ensure that the other members of the Circle would conceive children as well. This news did not sit well with Diana. Turns out that Amelia was the one who brought Blackwell into the Circle in the first place. Like mother, like daughter. Also alike are Diana and her mother. Both (accurately) blame the Blake girls for bringing Blackwell into the Circle. The last piece of the crystal was placed in the trophy case at the school, placed there by Adam's grandfather so that Amelia could retrieve it if she wanted to.
Diana discovered that Charles killed Amelia after Blackwell used magic to make him think that Amelia was getting revenge because he killed her. After all of Diana's fulminating against Blackwell for what he has done, discovering that her dad killed Cassie's mom was too much and she left him and ended up crying on Grant's shoulder. Not a good day for the half-sisters.
Melissa also had a bad day. First, she discovers that her boyfriend is back from the dead but is not the same as he was. Then Jake yells at her because he is trying to deal with what is going on himself. Finally, she is forced to kill Nick in order to save Jake's life. Life sucks sometimes.
Whoever is feeding Eben power is powerful. He was able to take on Blackwell without breaking a sweat. And he now has Faye as his prisoner. Fortunately, the Circle has the final crystal piece. Unfortunately, it is currently in Blackwell's hands.
Next week, season finale.