Previously: Trinity's a serial killer given to random weeping. Dexter found him but decided to hold off killing him until he learns how to be the successful family man Trinity is. Lundy got killed, Debra finally decided Trinity did it. And she also decided she figured out the C.I. her and Dexter's dad was fucking way back when.
We open on Dexter and family (Deb included) out for a peaceful boat ride. I always forget Dexter's boat is called the Slice of Life. Yet another reason for everybody in Dexter's life to slap their foreheads if and when he's ever caught. Everybody seems to be enjoying the blissful relaxation, but Dex gets a call from work, so they have to return to shore. Deb also exposits that she's returning to work and that she's now going to be living in Dexter's old bachelor pad. The better to one day find an incriminating piece of evidence that leads her to discovering he's a murderer, one assumes.
Dexter ventures out to the murder scene, which is in the swamps. There he sees an alligator with its belly sliced open. Man, whoever's killing those gators is SO gonna pay! No, actually, the gator's belly has an arm in it, and before you start thinking it's weird that Miami PD would just randomly find an arm-eating gator conveniently gutted for them, one of the swamp locals notes that he was planning on eating the gator when he discovered the surprise limb. Dexter examines the arm, which appears remarkably undigested for having been in a stomach, and, noting the ligature marks on the wrists, concludes this is a homicide and not simply a gator-munching. Angel says they should search for further body parts. Dexter would very much appreciate a head.
That night, Dexter returns home to a house full of yappy kids who need attending to. He is but one man, people! (DVO notes that he's kinda two men, but we're ignoring DVO.) Dex sees a business card from Christine Hill atop Debra's stuff. Rita says she's called a couple times before, wants to do a hero piece on Deb. Dexter obviously wants nothing to do with a reporter snuffing around his family -- and by extension, him. Dex and Rita overhear the neighbor couple fighting, which gives them the opportunity to remind us they they're still in counseling and are doing much better now.
The next day, Dexter stakes out Trinity at the hardware store while DVO lays out this week's broad strokes: "I'm a serial killer, and I need advice on how to keep my kids from taking over my life." So once again Dex turns to Trinity for lessons in living as a Complete Man. Dex offers to help Arthur load up his car -- sometimes serial killers just love the classics -- and asks after Arthur's son, Hot Jonah. Though probably not for the reasons I'd be asking after him. Trinity notes that Jonah's got ROTC in the morning and football in the afternoon, so no time to help the old man. And rather than let that suffice, we get the follow up for the back row, where Arthur explicitly states that he's trying to push his children out into the world so they can be their own people. All that flies right over Dexter's head, and all he can hear is "get the kids out of the house." After fishing, unsuccessfully, for Arthur to invite him over, Dexter finally lies that he's new in town and without his family, he doesn't know anybody. Arthur's aloofness dims for a moment, and he asks Dexter what he's doing this weekend.
At Miami Metro everybody can't wait to welcome Deb back, including one gloriously uncomfortable hug by the coffee truck. And the coffee's even free! As you can imagine, Deb takes to this excessive attention like it's a swarm of back-patting bees. She tries to slip inside quietly and asks Dex to run interference with an approaching Christine. Dex takes a pretty firm stance with Christine from the get-go, no false pleasantries -- Deb's been through enough, she needs to be left alone, leave her alone. Quinn sees this and asks to speak to Dexter alone. He says Christine's just trying to do her job and Deb can take care of herself. They take turns puffing out their chests and posturing, before Dexter hits with the hard stuff: "The guy who saw the other guy steal the money from the crime scene wants Christine kept away." Message received! Though Quinn is getting that "Must take Dexter down" glint in his eye.
Inside, Debra rushes into the briefing room, late. She apologizes but quickly admits her late entrance was on purpose: "I was waiting at the end of the hall so I could tell you all at once and get it over with." She thanks everybody for their concern, but she doesn't need anybody's help, and she's not going to show anyone her scars (pointing to Quinn). "So please, can we just fucking move on ... and why is there a picture of a fucking arm up there?" LaGuerta, barely suppressing a giant smile, welcomes back "Detective fucking Morgan."