I did see an interesting theory that Sarah was infiltrating Kacey's life paralleling Cameron's origin as an infiltrator--trying to get her to trust Sarah so she wouldn't be bringing her ex the nosy cop around.

No, Derek wasn't in this episode at all. And yes, they had the voiceover last season, but it was Sarah talking in the first person, and much less annoying, I thought.

Apparently the rating this season kind of suck? I was just reading that it might be cancelled. :-(