Jack hasn't come out of his room as he wallows in what he did without a soul. As they discuss what lays before Jack, the AC goes out. Dean enlists Sam to help him tackle the pipes. After all, they conquered the devil and killed Hitler.
Dean decides to reset the system against Sam's better judgment. When Dean returns to burgers, there is a woman in the kitchen.
She's a wood nymph. Being in the woods nymphing is a young one's game. She claims to live in the bunker. She took care of the cooking and cleaning and stuff. The Men of Letters were her boys, here family.
When Dean suggests she leave, Mrs. Butters is hurt. She thinks it's 1958. She doesn't know how to react to 2020. All of her Men of Letters are gone, with only Sam and Dean remining.
Dean is not good with emotion.
Mrs. Butters remembers the day the Men of Letters left and never returned.
She placed the bunker and herself in standby mode to keep the place safe. And she only resurfaced because Dean reset it.
She worries about them. It's probably been an age since they had a homecooked meal or celebrated the holidays or, ew, washed their clothes.
It turns out they have a monster radar. Her magic is imperative to the bunker's function. She pants to send them to clean out a next of vipers so they can return in time for supper. Hell yeah, Dean says.
Dean wants to believe she is all she says, while Sam worries that maybe she's not to be trusted.
Dean says they should check out the vampire nest to see if she's all she says. If it doesn't pan out, then they'll deal with it.
Dean warns Jack about Mrs. Butters, who is busy making snickerdoodles. I like her very, very much.
Sam continues to fret, while Dean continues to slough it off.
Mrs. Butters decides to care for Jack, knowing he's going through a hard time. She makes him a sandwich and leaves it outside the door.
The nest is alive with activity -- activity that includes watching vintage episodes of Dark Shadows and drinking blood from a Slurpee cup.
Sam and Dean arrive and make short work of them. Dean is seriously impressed with monster radar.
They arrive home to Christmas in all of its regalia. There is a big tree and a train circling it. Dean is absolutely thrilled.
Mrs. Butters thinks they need to celebrate their wins. Sam is skeptical, but it does lure Jack out to the kitchen. Mrs. Butter wonders what Jack is, but she accepts him if the boys vouch for her.
Poppycock. Of course he's hungry. Worried about Dean's cholesterol, she gives him tomato juice, but she gives Jack what appears to be a creamy smoothie.
The monster radar goes off, and the boys grab their bagged lunches, and off they go, leaving Mrs. B and Jack alone to do dishes and bond.
Jack shares with Mrs. B what he did to Mary, and she tells him that we all do things we're not proud of, but life gives us second chances, and it's our obligation to hold onto them.
After their chat, Jack gets another smoothie.
Sam and Dean fight and eat and fight again, celebrating holidays every day of the week under the care of Mrs. Butters.
They settle into a nice routine. And it's Sam's birthday!
And then, Jack wanders in on Mrs. Butters going through the files. She has a concerned look on her face. After asking for another smoothie, Jack investigates and finds a file on her that has a film reel.
Cuthbert Sinclair is on the film sharing the story of Mrs. Butters, who destroyed upwards of 200 men before she was restrained. Wood Nymphs react violently when home or family are threatened. He uses Mrs. Butters for service and security, and has a test showing her destroying a man who is no longer of use for them by ripping off his head and suggesting cookies.
Sam has a date! He wants to cut his hair.
Mrs. Butters fixed the TV in the Dean Cave. He's still thrilled. But Jack is very worried, and even more so when she high tails it to the room with the markings on the ground.
She says that Jack relished the pain the man suffered when he watched the video. He wonders if it's some kind of test to see if she's bloodthirsty or dangerous. She's trying to protect Sam and Dean, who should be scared of Jack. She tosses him to the ground.
Mrs. Butters has weakened Jack with the smoothies. He doesn't understand. She says she's done it to make the bunker safe again, to get rid of all the monsters.
Mrs. Butters tells Dean what she did and how she's trying to protect them. But going full Nurse Ratchet grates on Dean's nerves. He looks at his sandwich with chagrin.
If they can go downstairs, let Jack go, and forget this ever happened, then all is well. Instead, Dean joins Jack.
Sam arrives home, after curfew, wondering where Jack and Dean are. She has some good news and some bad news.
She lies and says Jack has taken over Dean's mind. They're both downstairs ready to be killed by them. Sam acts very happy that she's done it and says he'll get his gun so they can get to the killing.
They have no idea how to kill Mrs. Butters. By phone (Dean didn't call for help so Sam could enjoy his date), Sam and Dean worry over theories.
Dean has to admit to Jack that he's trying, but it's not easy to forget what Jack did. Still, he's not going to let some evil Mary Poppins take him out.
When he pulls the gun, she gets him under control. He's her favorite, so she doesn't want to give up on him -- yet.
Mr. Cuthbert taught Mrs. Butters that people can learn through pain, so she pulls off Sam's fingernail.
Also talking about pain is Dean, who uses it to break down the door so that they can rescue Sam. They immediately race to the reset. She's gone. But the symbols are glowing and the control room shaking. Bitch is free! And she's glowing. They've all been very bad, she says. She refuses to fail. She won't let Jack destroy her family.
Sam uses logic. How does hurting people they care about protect them? She challenges with what she learned from Mr. Cuthbert. But Sam and Dean override her. Jack can save the world, and Cuthbert lied to her. She cries. She misses them all so much.
But she does heal Sam's nail and apologizes.
Even Jack forgives her. She would love to see the woods again, see the sun streaming through the trees. She has such fond memories. They pack her up and send her home, and they'll once again be on their own without her magic.
She offers parting advice and leaves.
Jack worries that he's supposed to kill God, and he got fooled by Mrs. Butters since he was stupid.
Jack made a birthday cake for Jack. It's not perfect, but it's definitely cooked with love. And Dean? Well, he loves his apron.