In this episode, we get a chance to dig into Mick Davies' background. We discover through flashbacks that as a child, he attended a school run by the Men of Letters known as Kendrick's. In order to secure his place in the organization and prove that he could be of use to them, Mick was made to kill his young friend, Timothy. The ordeal haunts him in nightmares, but he firmly believes that he is ultimately doing good by following orders "without question." The Code must be upheld. It was for that reason that he killed the werewolf girl in the previous episode, but now he's having second thoughts.
In this episode, we see the return of Ilene, the deaf hunter that once helped Sam and Dean track down and kill a Banshee. She's found a lead on Dagon and Kelly Kline. She sends the information to Sam and Dean. The brothers stop back at the bunker before heading out and find Mick waiting for them. He brings news of a "cosmic shock wave" that the home office recorded a few months ago, so the brothers explain that they already know about the nephilim. Mick is furious that they didn't kill Kelly when they had the chance, but the brothers defend their decision to leave an innocent woman unharmed.
Mick receives a call from Dr. hess, Supernatural's very own Dolores Umbridge who tells him, in no uncertain terms, that she wants the American hunters either under control, or exterminated by Mr. Catch immediately.
Kelly Kline is steadily growing larger. Recently, she has begun experiencing some strange pains. She demands that Dagon allow her to see a doctor to make sure that the pregnancy is progressing alright. Dagon agrees, reluctantly. At the doctor's office, Kelly gets to see an ultrasound of the baby boy. Dagon uses her power to make the doctor tell Kelly that everything is fine, despite the very concerning images that he sees on the screen. Later that night, a man shows up at the doctor's office. He makes the doctor disappear, along with Kelly's file.
Back at the bunker, Mick tells Sam and Dean a little more about how he came to work for the Men of Letters. He picked the pocket of a Man of Letters, looking for lunch money and ended up with a cursed coin, instead. The Men of Letters decided that he showed promise, so they sent him to Kendrick's to train.
The group decides that they need to get moving on tracking down Kelly Kline, so they get their things together and meet up later. Sam brings along Ilene, and Mick is forced to bring along Renny Rowlings, another member of the Men of Letters who was sent by Dr. Hess to keep Mick in line. He doesn't really get along with the hunters, but they ignore it. Dean moves in to collect Kelly on her way to see the doctor again. He brings her to the other. Sam and Dean try to offer their help again, a way to end the pregnancy, but Kelly resists. Renny objects a little more strongly, wanting to just kill the woman then and there, but the Winchester's won't allow it.
But before the argument can continue, Dagon arrives. She knocks aside the Men of Letters and the Winchesters like they're nothing. None of their bullets seem to have an effect. Both Renny and Ilean scramble for the nearest guns as Dagon leads Kelly away. Ilene gets ahold of the colt and fires at Dagon, but Dagon is already starting to disappear. The bullet wooshes through to a space where Dagon was and hits Renny in the heart.
The Men of Letters code requires that Ilean be killed as penalty for killing a Men of Letters. Mick sees what has happened and points his own gun at a very scared and upset Ilene. But he struggles to pull the trigger, knowing that it was an accident. He struggles against his training to blindly follow orders and decides to follow what he knows is right instead. He lowers the gun. Ilene and the Winchesters leave him to clean up the mess.
Dagon takes Kelly far away and cuffs her so she can't leave. Kelly apologizes for leaving, claiming that she was just trying to do what she needed to for her baby. Dagon scoffs at her, finally telling her the truth. The baby she's carrying is far stronger than Kelly realizes. The baby is in no real danger of dying, but Kelly will. The birth of a nephilim is always fatal.
While all of this is going down, Mary has been off with Mt. Catch, playing the living weapon and taking out whatever monsters the Men of Letters send them after. While they still very much disagree about about of things, they seem to be getting along rather well. The two have become physically involved, although they both hold no real feelings for the other.
Down in Hell, Lucifer has finally bent to Crowley's authority--or has he? He is making quite the show of bowing down to Crowley, but he's working his own angle. He is in contact with Dagon, keeping track of his child, while in Hell, looking for a way around Crowley's control over him. He's found some new demonic help that's taking a look at his vessel. He sends his spy off to find a way to turn off Crowley's control system.
At the end of the episode, Dr. hess herself shows up at the Men of Letter's American headquarters. She confronts Mick about the death of her personal agent, Renny, and Mick's failure both to control the Winchesters and to eliminate Kelly Kline and Ilene. Mick stands up for his decision, claiming that he did the right thing, even though it was against the code. For his troubles, he receives a bullet to the head. Dr. Hess declares the American experiment failed and orders the hunting down and killing of all American hunters.