Speaking of fucked-up life with Trinity, Scott wakes up to find himself in a dark basement with Arthur on the floor building a model train. It's official, model trains have officially become the sole province of the weird and dangerously maladjusted. Trinity calls Scott "Arthur" and won't respond to his questions. Instead, he plays with his trains and makes choo-choo noises.
At home, Dexter researches the previous Trinity killings and finds cases of abducted young boys in the same cities, the same time periods, five days before each bathtub killing. Since DVO and Harry are both working overtime to make sure we see the parallels between these lost boys and Trinity's lost innocence (not to mention Dexter's as well), I'm just going to focus on the police work. Unlike Trinity's other victims, the bodies of the boys are never found. He looks up the most recent child abduction, five days before the Lisa Bell murder. Dexter, making sure we get it, says, "My God, the boys begin the cycle." Rita then startles him by returning home with the baby. After a vaguely see-you-next-Tuesday-ish comment about how Dexter always seems to be working late, she says Harrison's not feeling well and will be sleeping in their bed tonight. Fascinating, Rita, BYE.
The next morning, Dexter fidgets, worried about where Arthur could have taken the boy. They could be anywhere. To that end, he gets a cop friend to run Arthur's plates (under the ruse that he wants to track down a guy whose car he rear-ended) and notify him when the van is spotted.
Outside Dex's office, Masuka paces nervously. He tells Deb he needs to tell Dex something, but he doesn't know how to say it. This is all because he saw Rita and Elliott kissing on Thanksgiving. But Deb doesn't investigate that far because she's next in line to visit her brother. She tells him she'll be granting Christine an interview today, but that she thinks Christine might know more about who killed Lundy than she's letting on. And I think Deb's more suspicious of Christine than SHE'S letting on, but it's not like Dexter's paying attention anyway. He does perk up when Deb wonders if she should take her suspicions to Quinn first. Dexter is understandably and predictably not in favor of telling Quinn anything, saying Deb doesn't know where his loyalties lie. Dex goes to make a swift exit, but Deb practically barricades the door. She's giving a Trinity briefing in a minute and needs Dex's big, juicy, chess-club brain.