I was starting to lose some faith here that certain loose threads had been dropped without any believable resolution; this episode makes me think the end of this series may actually not disappoint. Dexter finds blood underneath Cassie's fingernails he assumes belongs to her killer – and it's Zack's. While he buries that evidence, Quinn notices the similarity in MO as well, and that and the fact that Zack has cut off contact with both Dexter and Vogel makes Dexter as close to panicky as he gets. He resolves to kill Zack, and Vogel reluctantly signs off on the idea but cautions Dexter that killing Zack may now produce an emotional consequence for him.
With Quinn busy consoling a distraught Jamie, Dexter tracks Zack to a motel room in the Keys – which he discovers has been staged as a kill room a la Dexter. Dexter resolves to use it to kill Zack, but when Zack returns, he tells Dexter that he was actually after a murderer he knew in high school, whom as it happens he already just killed. He's able to prove his story, and Dexter is reluctantly kind of thrilled that his protégé followed the Code even without real prompting even as he kind of hilariously lectures Zack on all the details he got wrong.
Despite their almost overwhelming mutual attraction, Dexter resolves to get Hannah out of town with a new passport and identity. Deb fights with Dexter about her, of course, and she eventually dangles the large reward money that's out there in front of Elway to get him to go after Hannah – except Dexter has taken her with him in his pursuit of Zack. On the way, Dexter tells Hannah all about Vogel and Zack – unaware that Deb is still on his tail thanks to Elway's GPS tracker. With Dexter off dealing with Zack, Deb accosts Hannah, but she only ends up leaving the scene in disgust after Dexter and Zack show up, and later contemplates a return to the police force.
Dexter, Hannah, and Zack, like a weird adoptive family, head to Vogel's for dinner, but after the getting-to-know-you bit, Dexter is still bothered by the Cassie murder and wonders if someone might have tried to frame Zack for it. Afterwards, faced with Hannah leaving, she and Dexter finally do it, and he convinces her to stay – unaware that Elway is picking up where Deb left off.
Oh, and also? Dexter arrives home and finds Zack dead in his apartment…BY THE HAND OF THE BRAIN SURGEON. It's unseemly, but how many more times am I going to get to say I told you so? Speaking of which, I think I've got TBS figured out, but I'll wait until the full recap to tell you.
As people mill about Cassie's surely-cool-by-now corpse in the usual three-quarter speed that accompanies such scenes on this show, DVO tells us that, essentially, he's too horned up to focus on the crime scene. As if to drive home the point, the shot of Dead Cassie gives way to several sexy, probably-nude looks at Hannah, and even the murderess herself might think that transition was a little fucked up. Masuka snaps Dexter back to reality, and from the murder weapon being a decorative swan of Cassie's, they conclude that the crime wasn't planned and Cassie let the killer into her place voluntarily. This makes Masuka wonder if Oliver was the culprit.
Speaking of which, Batista is asking Oliver about his plans with Cassie that evening IN FULL VIEW OF THE CORPSE. (As my tennis coach says when I flub a particularly easy shot, "That's pro!"). After we learn Oliver is a structural engineer, DVO wonders if paying more attention to Zack might have saved Cassie's life, and then we see Batista consoling Jamie, like, "Can we take this outside already, or should we just have the funeral right now?" It's not like that much embalming is going to be necessary. Dexter notices blood underneath Cassie's fingernails and takes a sample, recalling that Zack and Cassie crossed paths once and then Deb turns up to the Let's Gawk At Dead Cassie party. (She didn't even bring a sixer!).
After Deb asks if Dexter's okay (he actually takes a long moment before telling her yes) she brings up Hannah, but before they can get into it Batista interrupts them and Deb wonders who would want to kill Cassie. When she realizes she's slipping back into her old Lieutenant role, she apologizes, but Batista tells her she's always welcome back, which would seem a bit heavy-handed given what's to come if he weren't such a staunch devotee of hers. She laughs that maybe she'll put an application in the mail before turning to Dexter and saying she'll return to finish their conversation, and Dexter's like great, "I need threats on top of everything else in my life."
The next day, Dexter meets Hannah down by the marina and tells her he needs to get her out of town ASAP, and he has a guy that can get her a new passport. Well, that's a claim the show can back up. She somewhat flirtatiously points out that he could have called with that news before telling him they missed a spot of blood cleaning up – it was on "the edge of the whiskey bottle," and you'd think they would have been a bit more careful given that she's making it sound like THAT WAS THE DEATH WEAPON, but her point is that "I was so glad to see it, because it reminded me of you."