You live by the code, you die by the code.
Just as they arrive back at the bunker, Sam and Dean see Mick sitting at the table. Mick begins to tell them about a cosmic shockwave that recently hot his radar but they already know – it's the Nephilim. Mick is stunned that they never told him about it earlier but the boys tell him that they are handling it in their own way as he would have killed Kelly and immediately. Meanwhile, in hell, Lucifer has chosen to submit to Crowley. As the latest king of hell, Crowley uses this opportunity to parade him around to the others like a dog as Lucifer did to him. Not willing to let the opportunity pass, Lucifer uses this chance to sway others that he is still the man with the plan and fully intends to take back what is rightfully his. After all, he's going to be a dad soon. Elsewhere, Eileen Leahy managed to get some info on the whereabouts of Kelly Kline. After Kelly recently visited a doctor for a checkup, a demon came to wipe away any trace that she was ever there. Luckily, Eileen managed to get Kelly's phone number just before she stabbed that demon in the heart. With so much confusion and uncertainty, the British Men of Letters have sent Renny Rollings (top of his class) to assist Mick with apprehending Kelly. After laying out their plan to catch Kelly, it all goes south as soon as Dagon shows up to claim her. In the end, Renny is dead after being accidentally killed by Eileen and Kelly is gone. For Mick, the code demands that anyone who kills a Men of Letters be killed immediately and now he's forced to choose between following the code and taking a human life.
Overall, The British Invasion was a good episode that had its fair share of ups and downs. To start with the good: Adam Fergus as Mick stole the show. Ever since The Raid, Mick has come to the forefront of this season as his unyielding loyalty to the Men of Letters was shaken in the face of the alpha vampire. The Winchesters saved him that there is another way to helping people; that the situations isn't as dichotomous killing or not killing. The result was that Mick had a full character arc and was not the same person now as he was before. Unfortunately, the pacing of the episode suffered due to the scenes between Crowley and Lucifer as the other between Mary and Ketch. These scenes only served to slow everything down and took time away from building on the lore of the Men of Letters. The code is a great idea but we've never heard of it before now and I would have preferred if there was more time building on something that people will live and die by.
Although the scenes with Crowley and Lucifer, and Mary and Ketch served to set up story for future plots, they didn't have a purpose being in The British Invasion. As I mentioned above, they only served to pad out time for the episode but what's more, they didn't have any emotional impact in their own scenes. Can Lucifer be trusted to submit to Crowley? Obviously not. Does Crowley have another contingency plan just waiting to be used? Maybe but I'm not that concerned when Mick's world is being turned upside down. As for Mary and Ketch, it's clearly being set up that the two of them will eventually face one another and Mary will have to choose between Ketch and her boys. That is inevitable but having the two of them sleep together has little to no impact on the story besides getting a strange look from Sam and Dean whenever they find out. Mary and Ketch already have a connection but making that sexual doesn't add to their chemistry or to the season.
The biggest missed opportunity of The British Invasion was not ending on Ketch killing Mick. For the role that Mick has played in the season, the episode should have ended just as he started to confront Dr. Hess (who has apparently not aged a day since Mick was a child). It would have been abrupt and ended the episode on the exact moment that we started to root for Mick. His life wasn't easy and his conflicted character was done extremely well thanks to Adam Fergus but we all knew his time was coming to an end as soon as he started believing in the right thing rather than the code.
The British Invasion could have been a fantastic episode if the focus on the last episode where we would see Mick Davies alive. What the episode did do well is set up the coming battle between the Men of Letters and the hunters. But will they wait until the Nephilim is dead or choose to strike immediately? We'll see what happens in next week in The Memory Remains.