Synopsis of 12×21: “There’s Something About Mary,” had too much packed into one episode. Between the British Men of Letters killing American Hunters, brainwashing Mary Winchester and the Lucifer storyline, it was a rather painful episode to sit through and felt rushed and disjointed.
Aileen is hunted down by a borrowed Hell Hound and killed in the first five minutes of the episode. Dean and Sam discuss that seven hunters have been killed and they are still unable to find Mary. Dean and Sam realize that the Men of Letters were stalking Aileen, who left Ireland to come and stay with them. Dean and Sam search the bunker only to discover that the Men of Letters have been spying on them as well.
Mary is being tortured and brainwashed into a sociopathic master assassin and lead Hunter. She kills a fellow hunter and is unable to remember why she did it. Mary attempts to manipulate Ketch into killing her, but he refuses to do so. However, during this scene, Mary brings up the fact that her will was the only thing she had left, which she is slowly losing. This brings up some uncomfortable issues regarding consent and just added an extra layer of ick to an already convoluted episode.
Then in an attempt to throw in some added drama, it is revealed that Toni (the annoying blonde who tortured Sam at the beginning of the season) and Ketch used to be romantically involved and they are both vying to lead the new and improved sect of the American Hunters.
But wait, there’s more! Lucifer and Crowley have reintroduced this episode and have their usual witty sparring match. Lucifer decides that he is going to kill Crowley, but Crowley jumps ship to a rat.
The episode concludes with Dean and Sam kidnapping Toni. Dean and Sam plan on using Toni as leverage against the Men of Letters. However, Ketch outsmarts the Winchesters and turns the bunker into a death trap. On the bright side, he leaves sanctimonious Toni there to die with the Winchesters, so hopefully, she realizes the error of her ways.