Supernatural’ season 9 summons its 17th episode of the year in “Mother's Little Helper,” as Sam discovers Abaddon's plan through a decades-old Men of Letters case, while Dean struggles with his newfound impulses from the Mark of Cain.

Last week’s ‘Supernatural’ installment, “Blade Runners,” saw the boys partnering with a depleted Crowley to track down the First Blade, reaching back into Men of Letters history to obtain its whereabouts. So, what does the 17th season 9 episode bring? What strange and unexpected challenges will the Winchesters face next?

Read on for your in-depth recap of everything you need to know about ‘Supernatural’ season 9 episode 17, “Mother's Little Helper”!

In Milton, Illinois, teacher Karen Young returns from a long day of work, while her husband only seems interested in dinner that night. Surprisingly, Karen responds by bludgeoning her husband to death with a candle holder. Later in the Men of Letters base, Sam shows Dean the report, though Dean seems obsessed with poring over research to find any clues to Abaddon’s location. After Sam leaves for the case, Dean pulls out a bottle of whiskey.

The Milton sheriff denies signs of anything suspicious as he leads Sam to Karen’s cell, though the woman has since hung herself after scrawling in blood all over the walls. Sam calls Dean to update him on the situation, despite the lack of anything overtly demonic, after which Dean begins having vivid flashbacks to his killing Magnus last week. Elsewhere, a young teen named Billy hitchhikes down the road, recognizing his teacher when he pulls up in a van, though the teacher quickly attacks him with an eerie white light.

The same Billy enters a restaurant wherein Sam dines, before the boy gets violent with the people that know him, stabbing a woman’s hand out of pure irritation before Sam wrestles him to the ground. Billy seems only to be the latest of many violent townspeople locked up in the police station, but Sam finds no evidence of possession, only that the townspeople appear to have no remorse or justification for their actions. Sam calls Dean, who sits at a bar rather than continue the search for Abaddon, as Sam realizes that the townspeople’s actions remind him of his own after he lost his soul.

Sam sees a St. Bonaventure’s Convent van in the parking lot footage of the grocery store Karen Young had earlier visited, before an elderly woman visits the police station and insists that "those demons" are back. Sam pulls her aside to ask what she knows, as she identifies herself as ex-nun Julia Wilkinson, and reveals that her convent had been visited by the Men of Letters in 1958, specifically Henry Winchester and Josie Sands. Meanwhile, Crowley shows up to Dean’s bar in an attempt to figure out his mood, realizing that killing Magnus with the Mark of Cain has left Dean with feelings of both power and intense fear.

Julia explains to Sam how Josie and Henry arrived undercover to investigate another nun who’d apparently gone insane and killed herself, though the two repeatedly bickered about being sent into the field before their Men of Letters inductions. Entering the nun’s bloody room, Josie identifies the markings on the wall as belonging to the Knights of Hell. Later that night, Julia found herself attacked by the other nuns, waking up in a basement with a number of other innocents, who were dragged into a room and attacked with a white light.

Henry and Josie burst into the scene, exorcising the possessed nuns with ease, save for one who easily knocks out Henry. The head demon marvels at the idea of a woman like Josie joining the Men of Letters, but when the demon goes to possess Henry’s body, Josie offers her own instead, given her affection for Henry. Revealing itself as Abaddon, the demon accepts and jumps into Josie’s body, waking Henry thereafter and pretending they’d won. Back in the present, Julia believes the same attacks to be occurring at the now-abandoned convent.

Dean denies that the Mark of Cain instilled him with any fear or that he kills for any reason beyond protecting the innocent. When Crowley goes to the bathroom, Dean recognizes a fellow hunter preparing to follow him in and kill him, though Dean intervenes to advise the man against it. A short while later, Dean leaves the bar and Crowley behind, as we see that the hunter was actually a demon in Crowley’s employ, and they now believe Dean “ready.” Meanwhile, Sam arrives to the abandoned Convent to find a number of disembodied souls kept in jars, before being confronted by one of the surviving possessed nuns, Agnes. Agnes explains that Abaddon intends to build her own army of demons by corrupting human souls, while the convent is only one of their many factories. Sam struggles to exorcise the woman, sneakily utilizing a phone recording of the incantation when she grabs his throat, long enough to finally knife her. Sam empties the souls from the jar, which return to the dazed civilians in the police station.

The threat abated, Sam questions Julia why she never warned Henry about what she saw with Josie, Abaddon and the souls, as she explains that she left the convent in shame, for fear of what she’d seen that night. Returning to the Men of Letters base, Sam reveals to Dean that he was right to focus on finding Abaddon, now that they know her plan to raise a demon army.

OUR REVIEW:

It's been an uneven run for 'Supernatural' season 9, as much as it bears repeating so late into the ninth season of a series that might as well be on cruise control by this point. Last week at least picked things up in the ongoing fight against Abaddon (or is it Metatron? Which battle is more pressing, here?), as Sam and Dean finally got their hands on the first blade, and Dean's Mark of Cain began to show some predictably troubling symptoms. For as little as the actual recovery seemed to accomplish, we at least had Mark Sheppard's ever-entertaining Crowley to show a few new colors to make the hour worthwhile.

This time around, Dean doesn't have very much to do other than stew in his apparent addition to the blade, while Sam goes off to investigate yet another past Men of Letters mystery that helps to illuminate their present situation. It's an interesting bit of exposition to show how Josie Sands came to be possessed by Abaddon, while Gil McKinney does a somewhat thankless reprise of his role as Henry Winchester, though it doesn't exactly feel as if the story really engineered enough reason for the brothers to experience it separately. Sure, we've got whatever remaining brotherly angst keeps the two cyclically pawing at one another to open up, while the nature of Dean's addiction hasn't quite been made clear, leaving Dean to gripe at Crowley for the hour before the deposed king cryptically mutters about him being "ready."

We'll have a few weeks off until 'Supernatural' returns for the home stretch of season 9 (with Misha Collins returning from behind the camera and the 'Bloodlines' imminent), but for now, "Mother's Little Helper" at least provided us a bit of rudder toward Abaddon's ultimate endgame and a bit of backstory to the Men of Letters that will likely gain greater weight in the coming episodes. Not only that, but last night's installment at least gave a few stylistic flourishes and a neat trick with Sam's cellphone, not to mention a lack of inexplicable Snooki.

Well, what say you? Did you get your fill of scary ‘Supernatural’ action? What did you think about the revelation of Abaddon's plans or Dean’s latest predicament? Give us your take in the comments, and join us again next Tuesday for an all-new recap of ‘Supernatural’ season 9 episode 18, “Meta Fiction,” on The CW!

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