The Secret Circle Season 1 Episode 6 (10/20/11)
Nick's older brother, Jake, shows up this week. He left Chance Harbor two years earlier, after causing major problems for Faye as her boyfriend and also for Adam when he stole from his father.
In this case, Jake and Cassie bond a bit as neighbors, especially when Jake saves Cassie's life from an intruder. But we later learn that Jake knows the intruder. She carries around a knife with her that has a crescent moon on it and Jake makes a reference that it's too soon for "bloodletting" after the girl (Simone) takes some of Cassie's blood.
Jake ends up killing her in a fight that Cassie witnesses, but he plays dumb and claims he never knew her before that day. Viewers know better, though. The episode ends with Jake talking to some mysterious man and swearing that he still is a loyal witch hunter. He's back in town to rid Chance Harbor of all witches and this man can trust him.
Elsewhere, Diana dumps Adam after his dad warns her that Adam and Cassie are destined for each other.
Grandma Blake also gives Cassie her family's crystal, which amplifies her powers, and warns her not to tell anyone else.