Teaser (flashbacks to the last episodes of the previous season):

Diverges from canon before episode 12.22.

An escaped Lucifer stands at the top of a mountain, surveying the world. Crowley hides in a mouse scurrying after his body. Mary Winchester and Ketch drive away after sealing Sam, Dean, and Toni Bevell in the Bunker. Castiel and Kelly Kline drive away from the portal to Heaven after killing Dagon.

Under the influence of Toni Bevell's training, Dean takes on a curse that nullifies magic to escape from the Bunker. Castiel and Kelly Kline flee to Denver/Golden Gate Canyon State Park, where Castiel wards a shelter. Lucifer flies around the world, making contact with political leaders. Toni contacts Dr. Hess. Lucifer tears Castiel apart limb-from-limb, as the baby is born. Sam and Dean use a device from the British Men of Letters to banish Lucifer to Hell. Sam closes the gates to Hell by curing a demon and then he dies. Kelly Kline gives birth to Lucifer's son and dies. A nearby lake turns into a portal to Heaven.

Heaven. Night.

Sam lies on top of the Impala next to a child Dean, watching fireworks explode in the sky. He looks softly at Dean. Suddenly, Dean and the fireworks freeze in place.

"Dean!" Sam yells, as he rolls over and tries to shake his brother awake. Dean remains frozen.

A circle of angels appear, staring at Sam. Sam bolts upright and slides off the Impala. He faces three of the angels, with his back to the car.

"So, it's true," an angel says.

"It's a miracle," another angel says.

Sam looks at them. "What's a miracle?"

"Do you remember what happened?" a third angel asks.

Flashback: Sam curing the demon. A huge ray of light swallows him. His glowing black-stained soul splits into the bars of a cage - that streak around the earth and then lock together. Lucifer disappears and Castiel's dismembered body falls to the ground outside of the shelter. A smushy-faced baby screams loudly: Castiel's body reforms with a glowing yellow aura and two bright souls float into the beautiful lake in the park.

"You are blessed. The first soul to enter Heaven through the new doorway," a fourth angel says.

"A blessed abomination," the fifth angel says.

Sam jerks around nervously to look at the fifth angel.

"See him, his soul yet bears the marks of his demonic taint," the fifth angel says.

The third angel says, "Yet he is here, brothers."

A sixth angel steps forward. "Leave him," the angel says. The other angels walk away and disappear. "Come," the angel says to Sam. "Walk with me."

Sam eyes the angel for a moment. He glances at the child Dean, still frozen, lying on the Impala, then he walks next to the angel. They take a few steps together down a dark highway and appear in a lush arboretum. The angel's stride doesn't falter.

"Joshua?" Sam asks.

"Perhaps," the angel says, as they stroll through paradise. "More than one miracle occurred with the birth of Lucifer's son. The bells of Heaven rang. A second doorway to Heaven appeared. A new world was born-"

Sam startles, but the angel continues to speak as if Sam did not react. They walk down a path in the arboretum, surrounded by lush greenery, flowers, hanging plants, vines, under the arched branches of tall, tropical trees.

"Lucifer is trapped in Hell, and his son did not save him..."

"Wh…" Sam starts to ask.

"Castiel took the child and has hidden him from us," the angel says calmly. The path they walk on gets darker. "But we have a task for you, if you choose."

The angel stops. The trail continues into darkness. "We do not know where this trail leads. It appeared here. In the heart of Heaven. In the Garden."

"And you want me to find out?" Sam says.

"Yes," the angel says. "Lucifer's child blessed you. It is you or the child's mother who may most readily enter and return."

Sam looks at the darkness, then at the angel next to him. "How would I come back?"

A ball of dull-brown jute twine appears in the palm of the angel's hand. He unwinds it and Sam reaches out and takes one end of the twine. "Do not let go of the end," the angel says.

Sam ties the twine around his finger, then looks at the angel. The ball unwinds as the angel stands there. Sam steps into the darkness.

British Men of Letters Installation.

A Control Room.

Washington, D.C.

In the sterile, cold steel room, filled with monitors, Dean sits tensely in an office chair and watches a news report:

Two reporters sit in front of a map. The woman reporter shuffles papers on the desk and says, "In an abrupt turn of events, President Rooney has issued an executive order to start construction of a wall between Mexico and the United States and between Canada and the United States. The legalities of this are unclear and yet to be decided as a district court judge ruling in …."

Ketch and Mary Winchester walk into the room. Dean leaps to his feet and says, "Mom!" His mom ignores him.

Mary Winchester says, "The situation is worse. Lucifer's influencing events even with Hell shut."

Arthur Ketch responds, "That's only to be expected. Closure of Hell won't keep an archangel trapped for long."

"That poor boy. His sacrifice bought us time to plan," Mary says.

"Mom, Sam was your son-" Dean bursts out.

"Cool it," Mary says coldly.

Dean freezes.

"Toni needs to accelerate his training," Mary says to Ketch.

"Mary, let us go to another control room," Ketch say solicitously. "This hunter appears … overly excitable."

Dean says. "I'll leave. I'm done watching." He walks out of the room. Tears run down his face.

On the TV, the scene shifts to a woman standing by a highway where Army personnel are constructing a wall. "The practical aspects of building a wall between the United States and Mexico, much less Canada, remain yet to be addressed. And President Rooney's hardline stance has been met by sanctions from..."

"What does Dr. Hess plan?" Mary asks.

"Well, it's unusual to intervene at this level internationally, but given the circumstances, I think she'll have us remove the current world leaders who are under Lucifer's influence. The conference in Strasbourg, and then Malta, will do for Europe - we won't be involved in those operations. We'll be able to ward the successors. It relies on witchcraft, which the Men of Letters stand against, but again, the unusual circumstances," Ketch says stiffly.

"Yes. So we'll be on the team for the United States?" Mary asks.

Ketch gives a curt twitch of his head. "We'll kill President Rooney, then head north to Canada. Lady Bevell's team will handle the capitol buildings and residences as we proceed. Oddly enough, she believes that 24 Sussex Drive will be more complex to ward than the White House."

"Do you trust her?" Mary asks.

"I trust her competence in these dire times. Even with that … yahoo on her team. You know what I think of her, personally," Ketch says.

"I do," Mary gives him a smile. "As far as the bigger picture goes," she sighs. Mary slips her hand into his. Ketch squeezes her hand. They go back to watching the news report.

"...Thank you," the reporter says, as she finishes an interview with a young soldier working at the site. "And back to you Liliana..."

British Men of Letters Installation.

Central Control Room.

Washington, D.C.

Dr. Hess, Toni Bevell, and a British Men of Letters agent stand in a loose circle.

"He'll be greatly weakened as he breaks through, but if I have-" Toni says.

Dean bursts through the door into the Central Control Room.

"Ah, Dean," Toni says. "Welcome, join us."

Dean walks to the group, a haunted look on his face.

"We were just discussing a matter of importance related to you," Toni says. "I want you to lead the warding on the White House buildings. I cannot be distracted by the possibility that Lucifer could break through to Earth at any moment. Dr. Hess, surely-"

Dr. Hess says, "If Lucifer breaks through, the Old Men will act. Focus on your mission. The American Problem is yours. I am generously giving you this opportunity." She gives Toni Bevell a hard look, then turns away slightly, signalling an end to the conversation.

"Of course, Dr. Hess. I won't disappoint you." Toni looks at Dean and the two of them walk outside into the hallway. Dean eyes her warily.

"Oh, don't look at me like that," Toni says, in her best breezy, monologuing villain voice. "We're allies, for now."

"Allies," Dean says in a raw voice. "What did you do to mom?"

"I trained her, just as I was ordered to," she says.

"Trained," Dean repeats.

"I appreciate your family's sacrifice, Dean. Taking on the curse got us out of the Bunker. I would have taken it myself, but you so kindly stepped forward. And your brother. I changed my mind about him. He was a good man. Humanity has a fighting chance thanks to him."

"Are you training me?" Dean asks.

"Never think that. I would never train you, Dean," Toni says. "You're useful to the British Men of Letters as you are. The knowledge you have of current events and resources might be impaired if I trained you. Your mother on the other hand, was out-of-date and had nothing to offer."

Dean looks at her.

"I'm sorry for your loss. But I have no control over that. Now, you're a skilled witch," Toni says. "Let's resupply and check your hex bags and make sure the curse is suppressed before we proceed on the mission. You already have a criminal record in the United States. I'm sure another murder charge won't bother you too much. We need to move quickly."

Dean looks at her. He doesn't say anything, but follows her into a room filled with magic devices.

"Take a look around. I'm sure you'll see something you like." Toni gives Dean a sharp look.

Dean glares at her grudgingly, but walks to a shelf with a flat, steel box and unlocks it with a key he takes out of his pocket. Inside the box is a horn and a white rock.

Golden Canyon State Park.

Outside of Denver, CO.

A mouse scurries through the forest and along a log. A woman's leg appears, then the rest of her body: she's dressed in the taste of an elderly woman, but her face and body are young.

Next to the log, Crowley wakes up on the forest floor.

"My lord," the woman says.

"Tatiana, my dear. I am eternally grateful," Crowley says smugly. He stands, brushes himself off and kisses her hand. He straightens up and drops her hand. Crowley snaps his fingers and disappears, leaving Tatiana in the wilderness.

The scene flashes to Lucifer: he sits on his throne in Hell, speaking to himself quietly. "Run little mouse."

A Montessori preschool.

Gennevilliers, France.

The cheerful, orderly classroom is full of Montessori learning toys and children of varying ages from toddlers to Kindergarteners: buttoning shirts mounted on boards, drawing, doing geography puzzles, counting with sticks and blocks, looking at pictures of boats and vehicles laid on a cloth on the clean wood floor, painting, playing in a sandbox, watering plants, cleaning a mat, and sweeping. A teacher's aide and a group of children set places at small, child-sized tables for a snack.

Castiel stands at the doorway, carrying a toddler. He faces a slim, kind-faced woman in her thirties or forties and places two of his fingers on the woman's forehead. She blinks and speaks in French; the dialogue is subtitled: "Yes, of course. One day is fine."

"Thank you, Celine," Castiel says in French (subtitled in English).

"And what is your nephew's name?" Celine asks.

"He hasn't decided on his name yet," Castiel answers.

"How remarkable," Celine says.

"Yes, it is remarkable," Castiel says with a euphoric smile. The toddler watches the grown-ups curiously and looks eagerly at the school room.

"What shall the other children call him?" Celine asks.

Castiel looks at the toddler in his arms.

"Yom," Castiel says. The toddler squirms.

"Please, come in," Celine says. "You wish to spend the day with him?"

"Yes," Castiel says with a peaceful smile. Castiel walks slowly into the room.

"We're about to have snack time," the teacher says.

Castiel puts the toddler down next to a bustle of children of varying ages, from toddlers to Kindergarten-aged children. A teacher's aide stands by a child as the child carefully takes out a pan of mini quiches from the oven. Yom looks on eagerly, but stays close to Castiel. "Yom, and his uncle Castiel," the teacher tells the aide. The aide nods at them, "Julia," she says.

"We wash our hands when we come into the room," Celine reminds Castiel gently.

"Of course, it's a good idea to wash our hands before we eat," Castiel says. He washes Yom's hands as Yom looks around the room curiously. "Mortals are prone to a variety of illnesses that can be transferred by touch and especially when transferred from their hands to their mouths, diarrheal diseases among others," Castiel explains in a whisper. Yom gets off the step stool.

They look at the room. Castiel crouches next to Yom. "Perhaps we could help set the table for snack time," Castiel suggests. Yom looks at Castiel.

A cluster of children put heavy plates and napkins by each seat. Another child puts out glasses for water and a third child carries small pitchers of water to each square table. Castiel takes a stack of three plastic glasses from the teacher's aide and crouches again and hands it to Yom.

Yom awkwardly pulls a cup off the stack and sets it down on the table. He looks around and slowly takes off another cup, setting it in front of another seat.

Children begin to sit down at the tables. Yom puts a glass in front of an adorable little girl, a couple years older, but the same size as Yom - she's fine-boned and delicate. Yom smiles at her and she smiles back and says, "Merci (subtitled in English.)" Yom sits next to her. He looks up at Castiel. The children sing a song, led by the teacher. Castiel and Yom join in, as the teacher's aide puts out the mini quiches, small plates of green bean salad, and cut up pieces of poached pear for the children to serve themselves. Yom looks up at Castiel.

Castiel shakes his head and whispers, "It tastes like molecules to me. When I was human, food tasted wonderful." Castiel smiles at the girl sitting next to Yom. The girl serves herself a spoonful of pear, then passes the small serving bowl to Yom. She stares at them as Castiel helps Yom with the pear, but is too intimidated by Castiel to speak.

With Castiel's help, Yom takes a forkful of pear and eats it, mashing pear on his face.

"Good," Yom says in French.

Castiel backs away. He stands and stares as the girl giggles and says, "Pears are Teacher Celine's favorite."

Yom looks at Teacher Celine curiously.

A boy at the table starts to sing tra-la-la-la. He knocks over his water cup as he reaches for the pitcher - the teacher's aide rushes over to help. The girl next to Yom looks at the serving bowl of green bean salad. "Green beans," she says demandingly. Castiel stares on with a worried look, but Yom puts his fork down and passes the bowl to her without comment. He uses his fingers to pick up more pear.

"Nono," Julia, the teacher's aide, scolds Yom. "Your hands will get messy." Castiel clasps his hands nervously as he watches, but Julia wipes Yom's fingers with a napkin and hands him a fork without any supernatural incidents.