Having ruled the ex-boyfriend out, MM pegs Norma Rivera's boss, with whom she was having an affair, as the likely suspect in her murder, but Matthews pulls Quinn aside to let him know the "Hamilton" family are "friends" to MM. Confronted with Quinn, Angie, Dexter, and a cheek swab, Hamilton admits to the affair, about which his wife had found out, but assures them he didn't kill her. This is backed up by an interaction Dexter has with Hamilton's creepy son, whom an eyewitness later places at Rivera's around the time of the murder – but the guy later suspiciously recants his story, leaving Matthews to tell Quinn to drop the whole thing. I suppose this must be going somewhere?

Janet Thornton survives and gives Batista Yates' name, and when MM checks the place out, they find several corpses from victims dating back to 2008, all with the toes of one foot having been broken in lengthy sequence. Meanwhile, despite having recovered from Deb's attempt to kill him with no apparent ill effects, Dexter, it may surprise you to hear, is hilariously sarcastic and bitter toward both Deb and Vogel and completely over any warmth for family. However, Yates busts in and abducts Vogel, not even letting her finish the Mama Cass song she's listening to; when Deb discovers this, she rushes off to grab Dexter from the Yates crime scene.

Once Deb confesses she saved Dexter because she couldn't imagine her life without him, he consents to team up to rescue Vogel. Yates berates Vogel for sending Dexter after him, unaware that Dexter, with some unwitting assistance from MM, is closing in on his hiding spot – one of the currently-unoccupied houses he's done work in. Vogel tries to save the structural integrity of her toes by offering sympathy over the abuse Yates suffered at the hands of his mother, but when that doesn't work, Vogel resorts to impersonating his mother, which buys her time to call Dexter from Yates' phone and leave the call open so he can hear her.

With Elway's help, they get the location, and Dexter and Deb uncomfortably listen to Vogel perform her Psychopath Whisperer routine – only Yates checks his phone and figures out what's happened. When Dexter and Deb arrive, they eventually find an unharmed Vogel upstairs – but Yates is hiding under the bed just like he did as a child from his horrible mother, poised to strike out lethally at Deb. Dexter, however, figures him out and spectacularly impales Yates with a curtain rod. In the end, Dexter brings Deb and Vogel out on his boat to dispose of Yates and calls them his family. I'm still not convinced that Yates was the Brain Surgeon, but the show certainly wants us to buy that this is the subplot's end, so why not enjoy the happy/grisly moment?