Dexter's feeling guilty (and bitchy!) in the wake of killing the innocent (but douche) Farrow. So he decides to bite the bullet and re-balance the scales by killing Trinity. He gloms onto an out-of-town house-building excursion, during which he opens up (kinda) about killing a guy, and Trinity opens up (somewhat) about his own sordid past. He doesn't admit to his 30-year murder spree, but he does spell out the events of his sister's death and how he was made to feel responsible. So Dexter plans to kill him that night, only when he breaks into Trinity's room, no one's there. Turns out, Trinity is planning to meet the sunrise by jumping to his death at the construction site. Dexter gets there in time to stop him, and just as Dex thinks better of it and is ready to let him drop, the rest of the crew shows up to pull Arthur to safety. Going forward, Dexter may want to get a move on.
That's because the Trinity investigation is really chugging along. Debra can't keep it limited to just the bludgeoning for long, and while LaGuerta is intrigued enough to push for a full-blown investigation, Debra can't be on it because she's a victim of it. But Debra, via a happy accident and a flashing of Masuka, realizes that her gunshot wounds don't match a killer of Trinity's height. So, bad news: someone else shot her. Good news: She can re-join (and take lead on) the Trinity investigation.
Additionally, with Dexter out of town, Rita ends up in the company of Neighbor Elliot, who is finally making himself useful as a plot device by clearly leading up to becoming Temptation for Rita. And LaGuerta and Angel end their episode and a half of self-denial by doing it at work.
Previously: Dexter declined to kill Trinity so as to better learn family values from him. Miami Metro actually got a pretty decent jump on the Trinity investigation, discovering that he's been spreading the ashes of a relative at the crime scenes. Angel and LaGuerta promised their relationship was kaput. And Deb got approval to investigate the bludgeoning third of Trinity's murders. Oh, and Dexter killed a smarmy fashion photog who ended up NOT being guilty of killing his models. Oops.
So Dexter's in his Blood Shack, his voice-over is going overboard with an endless string of defensive, bitchy justifications for why killing Farrow was so totally not his fault. You know my rule with DVO -- I ignore until it gives me something good. Basically, Dexter's feeling guilty -- not only for killing Farrow but for not going after Trinity instead -- and he doesn't like feeling guilty. He even breaks Farrow's blood slide in half, since it doesn't meet the standards of Harry's code. Of course, he cuts his thumb in the process, the better to be a metaphor for his guilt.
At work, Angel presents Farrow as a former suspect, now a possible victim. LaGuerta leaps to the logical conclusion that it was Brand -- Farrow's assistant and the real model-murderer -- who did it, and the case is then passed off to two detectives who don't even get speaking parts, so let's consider this matter shelved for the week, huh?
Deb notices Dexter being extra fidgety, but she has no time to wonder why, as now it's her time to present her bludgeoning case. She's got a slideshow of the victims throughout the ages. In particular, she points out the smudges of cremains that show up in the crime scene photos -- the same as the ash found at the most recent bludgeoning. Alas, because this is Deb, she clicks one slide too far and reveals a shot of one of the bathtub victims, also with an ash smudge in the photo. LaGuerta has her shutter back to it. Deb tries to tapdance around the issue but Maria finally has her come out with it. So Deb explains that the ash has shown up in photos from the bathtub killings AND the jumper-suicides. That's the pattern, see; three in succession, every year or so, for the last thirty years. While DVO repeatedly hopes for his sister's case to get laughed out of the room, LaGuerta is officially intrigued. Even when Deb gets to the part about Lundy investigating him, and how Trinity killed Lundy and shot Deb.