This season of Dexter isn't wasting any time getting to the main storyline. Last episode introduced Julia Styles as a victim of Boyd Fowler's. She also witnessed Dexter murder him. Now we see how she fits into the show.
Styles's character, Lumen, has a tough time trusting Dexter. It's hard to blame her when Dexter's still keeping her locked up.
By the end of the episode, Dexter managed to convince Lumen he wasn't going to kill her. That's when things got interesting.
Now it's clear the remaining episodes of the season will feature Dexter and Lumen hunting down the others in Boyd's abuse and killing gang. It's an interesting premise: revenge. I know Dexter doesn't have a personal stake in this ring, but in a way, it's an extension of the first kill since Rita's death. We know Boyd didn't do it for Dex, but maybe the others will give him his grove back.
Partnerships haven't worked out in the past for Dexter. First Miguel Prado, then Trinity. Obviously Dexter's dealing with a traumatized woman, not a bloodthirsty individual. Still, involving another always leads to trouble, and I can't understand why Dexter keeps doing this to himself. On the other hand, what else can he do?