The crazy pace isn't slowing down. Little things first: Quinn drops Nadia off at the club, and when Isaak Pullo and Jason Gedrick see him, Isaak Pullo has Jason Gedrick leave a bag of cash in Quinn's car just like old times; also just like old times, Quinn keeps it. Hannah turns up to the station to talk everyone through her road trip with Randall and to locate the rest of the bodies. She tells Batista that she was really scared and fearful for her life before Randall was caught, but Dexter sees through her and realizes she's nostalgic for those days. Hannah does lead them to the bodies of two victims who were a couple, and Dexter's analysis reveals that the woman was not killed by Randall but by Hannah -- a detail he chooses to withhold. Later, he tells her what he knows, and she admits it without admitting it. So she's probably not the greatest person, but honestly Dexter at this point could use an ally who's no stranger to violence, as the rest of the episode will show.
Dexter, while cleaning his boat, finds some of Greene's blood. He's stunned when a test reveals the blood's owner, and when he gets home, he realizes that someone has been in his apartment, and might still be -- and is, as it happens -- Isaak Pullo is sitting inside with some scary torture tools and a gun. Dexter leaves a fake message to lure Isaak Pullo out, and when he sees him, he recalls that they've met before and realizes that the Brotherhood must be coming to exact vengeance for Viktor. Dexter and Isaak Pullo then have a little phone chat in which they lay bare all their respective information, and when Isaak Pullo tells Dexter he's not going to stop with him and threatens Deb as well, it is on. Fearing for her safety, Dexter is forced to come clean to Deb about everything that's gone on with the Brotherhood, and when she hears it all -- Dexter withheld crime-scene evidence, the bartender suicide was a setup job, she's now involved in covering up Murder Number Three -- she feels like she has to do something and resolves to arrest Isaak Pullo. Dexter, however, prevails upon her to let him handle the situation while the two of them go into semi-hiding, and that night, while they share a cheap motel room, they fondly recall their childhood bond.
Dexter tries to get someone else to do his dirty work for him when he lures Isaak Pullo into a bar controlled by those Colombian rival heroin dealers -- but when MM turns up on the scene, they find only dead Colombians and no Isaak Pullo; not only that, Dexter is forced to tell the story of how Isaak Pullo single-handedly fought his way through multiple attackers. Fortunately, though, Dexter does discover Isaak Pullo's blood at the crime scene, so MM hauls him in. Dexter goes to see him (sorry, show, but I don't know how he would explain THAT), and Isaak Pullo makes it clear that he will wait years and travel parsecs to exact revenge upon Dexter, whose reply is essentially, "Bring it."
Masuka is on some jag about how he thinks he's getting fired, but it turns out he's jumping to this conclusion because he heard from a colleague that LaGuerta has been processing evidence at a private lab. When Deb hears the details, she goes to find out what LaGuerta is doing, and LaGuerta, seemingly softened by her mistaken perception that Deb is showing an interest in the Bay Harbor Butcher stuff because of her relationship with Keith Carradine, confides in her that she thinks the Butcher is still alive, especially since the fact that the Department never released the blood-slide detail to the public makes the possibility of a copycat almost nil. She also tells Deb that she never believed Doakes was the Butcher and that Keith Carradine had his doubts too, and Deb, feeling some real conflict, admits that she knew Doakes to be a good man. Deb offers to help, so LaGuerta hands over her file, telling her it's got to stay strictly between them.
After an awesome freakout in the elevator, Deb goes to Dexter and tells him what's up, and it turns out LaGuerta has actually really been working on this, as she's catalogued a bunch of disappearance cases since Doakes died that she wants to check into. Dexter is forced to admit that three of the people on her list were victims of his, but only one of them, a wedding photographer Dexter abducted at a job, has family in Miami, so Deb resolves to make sure she's the one that talks to them. Dexter is not thrilled that Deb is getting her hands quite this dirty, but it's a good thing she does, as LaGuerta ends up tagging along, and soon, the victim's son has given them a bunch of photos from the wedding, and Deb's worst nightmare comes true as she sees Dexter in one of them. Thinking quickly, she suggests they take the photos back to the station so they can give them a proper going over; in the end, she turns up to Dexter with the photograph and news that she accepts what he does -- she just doesn't want to know about it anymore. We'll see how long that lasts, but it does feel like the closing of a mini-chapter.
So stupid Harry is hanging with Dexter as he cleans his boat, and this is easily the worst part of another jam-packed episode, so suffice it to say that despite the fact that Harrison is apparently coming home soon and Deb has been off Dexter's back, Harry feels the need to torture a metaphor about the ocean and the waves and the salt water and SHUT UP. However, we get somewhere when Dexter discovers some blood left behind from the timely exit of one Louis Greene from this show, and aspersions toward Jason Gedrick's cleaner abilities aside, has it not rained in Miami in the weeks since Greene became the victim of his own video-game concept? Now that something is actually happening, Harry is nowhere to be found, but Dexter gets out his forensics kit and quickly realizes a murder about which, for once, he knows nothing happened on his boat. He takes a sample.
Oh, look, here's Masuka whining to Quinn, of all people, that he should tell him if he knows anything about him getting fired, like, since when do these two even talk and why would Quinn know anything about anything? If he were still dating Deb, I could see it, but I barely remember that even happened at this point. Quinn apparently can't stand Masuka to the same degree I can't, which is definitely causing me some cognitive dissonance, and after Masuka blathers about how he took a paralinguistics course and he can tell Quinn is lying, Quinn positively barks at him to go away, and at least Masuka understands people's vocal cues enough to know he's not kidding around.
However, Masuka runs straight into Deb and asks her if he's getting canned, and she does seem like the logical person to whom to direct this question, so I still don't know what all this nonsense with Quinn was in aid of, but Masuka does actually have a reason for running around like a headless chicken in a state of arrested development, as he learned from a friend about LaGuerta farming out the Colin Hanks blood slide to a private lab. When Deb hears Masuka babble those certain keywords, she obviously silently freaks, but she holds it together enough to assure Masuka that LaGuerta is probably just alleviating his workload and that she'll look into it...
...which she does, immediately. LaGuerta dissembles at first, but when Deb's sharp eyes spot Keith Carradine's FBI notebook sitting prominently atop LaGuerta's desk and Deb asks if LaGuerta might be checking into the Bay Harbor Butcher case, LaGuerta gives her an appraising look and then has her shut the door and have a seat. She asks Deb for confidence before telling her about the slide with Colin Hanks' blood on it and her theory about the BHB still being alive. Deb weakly points out that Colin Hanks' death didn't exactly fit the MO of the other BHB kills, but LaGuerta's counter is that the fact that the BHB kept blood slides was a detail that was never made public, so the chances that someone else would have copied the MO are almost nil. Of course, if the BHB were in law enforcement, there's no reason to think a copycat couldn't be as well, and a law-enforcement officer could have been privy to the info; still, LaGuerta's theory has merit even if you don't know what Deb does, which is borne out by Deb admitting that she can't come up with any other theory that fits the facts.