After getting pressure from the chief this week, the squad really needed to make progress on the Fuentes case - and Deb made sure she did. Faced with a similar, hostage-held situation as last episode, she didn't hesitate and shot on of the bad guys dead.
She and Quinn also took major steps in what is now a series relationship. He's even talking about moving in together! Of course, Deb has no idea that Quinn also told his dirty narcotics friend to take whatever measure is necessary to learn more about Dexter.
Speaking of that serial killer... he gets closer than ever to Lumen. She tells him about the men that beat and raped her, and then something major takes place: we see a man get into a car accident with the barrels of women in the back of his truck. They get sprayed all over the road, as he runs away from the scene and isn't present when the cops arrive.
But they determine that the truck is registered to the motivational speaker Boyd had been listening to, Jordan Chase. He soon arrives at the station in order to clear his name, claiming the truck had been stolen. He brings with him his head of security, Cole, the same man viewers earlier saw clearing the bodies out of the swamp and driving the truck.
Lumen recognized Cole as one of her captors. We also see Cole and Chase talking privately and it's clear they were involved.
By the end of the hour, Dexter trusts Lumen enough to actually bring Harrison over and introduced these two to each other. No way Harry would approve of that.