Season 12, Episode 17:
The British InvasionThe British Men of Letters aggressively take control of the hunt for Kelly Kline and the Nephilim she's carrying.
Body CountFor this episode: 4 humans
For the series so far: At least 1330 humans (of which 22 were witches), 1132 angels (2 of which were archangels), 193 demons, 78 vampires, 59 ghosts, 36 Jefferson Starships, 22 gods, 19 zombies, 19 werewolves, 11 hellhounds, 8 Bisaan, 7 shapeshifters, 7 skinwalkers, 6 changelings, 5 djinn, 6 reapers, 4 dogs, 4 ghouls, 4 Leviathan, 3 Khan Worms, 3 Thule, 2 Amazons, 2 arachnes, 2 kitsunes, 3 rugarus, 2 vetalas, 2 zannas, 1 banshee, 1 cat, 1 crocotta, Death, 1 deer, 1 dragon, 1 fairy, 1 familiar, 1 lamia, The Mother of All, 1 nachzehrer, 1 okami, 1 phoenix, 1 pishtaco, 1 Purgatory creature, 1 qarin, 1 rakshasa, 1 rawhead, 1 shojo, 1 shtriga, 1 siren, 1 soul eater, 1 Titan, 1 wendigo, the Whore of Babylon, 1 wicked witch, and 1 wraith
- Anyone Can Die: Many fans thought Mick was about to do a heel-face turn and join Team Free Will only to have him unceremoniously killed during his own character-centric episode.
- Big-Bad Ensemble: In addition to Lucifer, Dagon, and Crowley already running around, Dr. Hess seems set up to take a spot on the roster as well, ordering Ketch to wipe out all the American hunters.
- Boom, Headshot!: Mick gets shot in the head mid-sentence by Ketch.
- Cardboard Prison: Hell is this for Lucifer. Crowley can't seem to be distrustful enough.
- Character Death: Mick is killed for standing up for the Winchesters.
- A Death in the Limelight: Mick Davies.
- Disappointed in You: Dr. Hess has Mick killed for standing up her, despite bringing up his loyalty to her (and being reminded of what he made him do when he was a kid).
- Hard Work Hardly Works: Averted. When Dr. Hess is explaining how far Mick and Timothy have come in their studies, the camera angle indicates that Timothy was naturally talented, while Mick was a hard worker. Mick is the one who "wins".
- HeelFace Door-Slam: After the time he spent with the Winchesters and how it changed his attitude, Mick's The Reason You Suck speech made the audience think he was about to emerge as a new ally for the brothers. However, his change of heart was cut short by Boom, Headshot!.
- Intangible Man: Dagon dematerializes when Eileen tries to shoot her with the Colt. Unfortunately for her, the bullet hits and kills British Man of Letters Renny Rawlings.
- Kick the Dog: Dagon tells Kelly she's nothing but a disposable carrier.
- Mistaken for Gay: The doctor Kelly sees briefly wonders if Dagon is Kelly's "partner".
- My God, What Have I Done?: Eileen accidentally shot Renny Rawlings while trying to shoot Dagon.
- Redemption Equals Death: Mick turns his back on the Men of Letters' rigid code to defend the Winchesters, and gets shot for his troubles.
- Running Gag: None of the Hunters care about Renny Rawlings, much to his annoyance. Eileen is still nonetheless horrified when she accidentally kills him.
- Shameless Self-Promotion: Renny is quick to list off his honors and achievements in the British Men of Letters training school.Eileen: No one cares.
- Ship Tease: Eileen Leahy seems to be hitting it off very well with Sam.
- Sudden Principled Stand: Mick takes one against Hess on behalf of the Winchesters. She has Ketch kill him for it.
- Sure, Let's Go with That: Dagon's response when asked if she's Kelly's birth coach.
- Tyke Bomb: Mick is revealed as one of these, having been ordered to kill his best friend when he was still a child.
- You Have Failed Me: Mick is killed for disobeying the code.